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1
Nixon, Andrew E., Marc Ostermeier e Stephen J. Benkovic. "Hybrid enzymes: manipulating enzyme design". Trends in Biotechnology 16, n. 6 (giugno 1998): 258–64. http://dx.doi.org/10.1016/s0167-7799(98)01204-9.
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Achmadi, Evita Riviani. "Enzymes as Potencial Source for Clean Label Bakery Product: Part 1, Mechanism and Application Single Enzym". Journal of Food and Agricultural Product 2, n. 2 (14 settembre 2022): 57. http://dx.doi.org/10.32585/jfap.v2i2.2708.
Testo completoAbstract (sommario):
Background: Increased public awareness of consuming healthy food has driven bakery industry to applied production methods and components of food products that are tailored to the market needs. Food product can be positioned as natural, organic, or free from additives/ preservatives which often referred to clean label trend. Bakery industry commonly using chemical emulsifier as component which improve characteristic and quality baked goods. Usage of chemical component is not appropriate with perception of clean label, although it is not yet clear what a clean label exactly means. Chemical emulsifier has potentially negative effect to health such as intestinal inflammation, obesity, metabolic syndrome and glucose resistance based on several research. Food enzyme can be alternative to replace chemical emulsifier and potentially source of clean label bakery product. Therefore, sustainable study was needed to find role single enzym as food additive and processing aid in bakery product application.Scope and approach: This review explain about the role single enzyme application in bakery product which discuss under three main headings include (i) enzyme as food additive and processing aid, ii) Characteristic enzyme to improve bakery product processing (dough mixing, fermentation, baking), sensories properties and appearance iii) Enzyme mechanism and application to enhance bakery product quality. Optimization of the role and function of enzymes can be conduct by enzyme quality validation through baking tests including formulation development, process parameters (dough rheology, handling machine and baking parameter), product appearance and sensory characteristics.Key findings and conclusion: Food enzymes play a role in enzymatic modifications as biodegradable proteins which not affected to nutritional value baked goods. Enzyme technology is a clean process with low energy consumption, low waste production, safe and less toxic working environment. Therefore, enzyme has potential to fulfill clean label trends and encourage researchers and developers in food industry to explore potential use of food enzymes in bakery products. Enzymes which usually used in bakery come from hydrolase class (amylase, protease, hemicellulase, lipase, xylanase and asparaginase), oxidoreductase class (lipoxygenase and glucose oxidase) and transferase class (transglutaminase). Application enzymes in bakery processs have their respective roles according to enzymes specific characteristics. Enzymes has the main role such as improve rheological and functional properties of dough according to baked goods type, enhance quality and characteristics baked goods including volume, crumb texture, color, taste and extend shelf life (antistaling). Sustainable research and development was needed to optimize the role of enzyme in baked goods by several approach such as (i) incorporation enzymes with other ingredients in the food matrix, (ii) parameters which affect to the work of enzymes in food systems (iii) potential of enzyme combinations to improve baked goods quality and (iv) understanding of usage regulation enzymes as food additives and food processing. Keyword: enzyme, clean label, food additive, processing aid, bakery product
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March, John B., e Jason Clark. "Enzymes by post—restriction enzyme stability". Nature Biotechnology 18, n. 3 (marzo 2000): 243. http://dx.doi.org/10.1038/73590.
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Städler, Brigitte, e Alexander N. Zelikin. "Enzyme prodrug therapies and therapeutic enzymes". Advanced Drug Delivery Reviews 118 (settembre 2017): 1. http://dx.doi.org/10.1016/j.addr.2017.10.006.
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Jovov, B., N. K. Wills, P. J. Donaldson e S. A. Lewis. "Vectorial secretion of a kallikrein-like enzyme by cultured renal cells. I. General properties". American Journal of Physiology-Cell Physiology 259, n. 6 (1 dicembre 1990): C869—C882. http://dx.doi.org/10.1152/ajpcell.1990.259.6.c869.
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Urinary kallikreins are proteolytic enzymes known to be secreted by distal nephron tubules. In this study, we demonstrate (using the chromogenic tripeptide substrate S 2266) that the renal cell line A6 from Xenopus laevis secretes a kallikrein-like enzyme. Secretion is present only when the cells are grown on filters, and enzyme is secreted only into the apical membrane bathing solution. Enzyme secretion consists of two components, one soybean trypsin inhibitor (SBTI) sensitive (SSBTI) and the other insensitive to SBTI (ISBTI). Both enzymes were inhibited by aprotinin, a kallikrein-like enzyme inhibitor. Using a bioassay, only the ISBTI enzyme produced a hypotensive effect on blood pressure and is thus a kallikrein-like enzyme. The apical membrane of cells grown on filters contains both enzyme species, whereas the basolateral membrane contains only the ISBTI (kallikrein-like) enzyme. Both enzymes were present in the apical membrane of cells grown on plastic. Initiation of enzyme secretion occurred after the cells formed electrically tight monolayers and the increase in membrane activity always preceded enzyme secretion. Using an irreversible inhibitor of the apical membrane-bound enzymes, the turnover rate for the SSBTI and ISBTI enzymes (cells on filters) was 3 and 7 h, respectively. Because the recovery of enzyme secretion was proportional to the recovery of membrane-bound enzyme activities, this suggests that enzyme secretion is due to the release of membrane-bound enzyme.
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Achmadi, Evita Riviani. "Enzymes as Potencial Source for Clean Label Bakery Product: Part 2, Mechanism, Application and Optimization Combination Enzymes". Journal of Food and Agricultural Product 2, n. 2 (16 dicembre 2022): 82. http://dx.doi.org/10.32585/jfap.v2i2.2709.
Testo completoAbstract (sommario):
Background: Food enzyme is important ingredient for bakery industry to improve production process, functional properties and characteristic bakery product. Food enzym can be applied as single or combination enzym based on purpose which is need on processing. Based on several literatures, application combination enzymes more effective than single enzym, due to synergism effect between enzym which combine. Combination enzymes can be mixed from same or different class of enzym, it is depended on selected specification and characteristic enzym. Application of combination enzymes commonly act as processing aid which added in flour while mixing process. Therefore, it is important to understand work mechanism of combination enzym in processing stage especially mixing, fermentation and baking. Sinergysm in combination enzym can be enhance using optimization method to improve quality of processing and bakery product. Response Surface Methode (RSM) with Central Composite Design (CCD) as a design experiment is the most effective and efficient method which commonly applied for modelling and optimization in food processing. This method helps to make informed decision on a process with the objective of improving efficiency and minimizing cost while maintaining quality.Scope and approach: This review explain about the role combination enzyme application in bakery product which discuss under four main headings include (i) Application of combination enzymes in bakery product ii) Mechanism combination enzymes to enhance bakery product quality include processing (mixing, fermentation and baking) and sensory properties (texture, taste, colour and appearance) iii) Optimization of combination enzym in bakery product using Respond Surface Method (RSM) iv) Regulation food enzym usage in United State, Europian Union and Indonesia. Evaluation mechanism, application and optimization of combination enzymes can be used as a base for sustainable development bakery product which is safe for consume and accordance to food regulation. The differences regulation between country can be considerate when supply and distribution chain of industrial and retail food companies stretch around the globe.Key findings and conclusion: The combination of enzymes provides a synergistic effect depending on the type and mechanism enzymes which is affected each other. Type and mechanism enzymes can be affected with process parameter and ingredient which is a part of food matrix while processing runs. Therefore, the suitability between process parameters, ingredient, specifications and characteristics enzyme are needed to gives significant results for optimization of enzyme combinations in bakery production. Understanding the role of enzymes as a part of food system is important as a basic knowledge in selection of enzymes to be combined. This helps researchers and developers to optimize the combination of enzymes by taking into account conditions of the process stages in bakery production. RSM with CCD as design experiments is the most efficient method because its only requires a small amount runs. CCD uses the build-up principle to build a quadratic model using the information gathered from the 2n factorial design. If the linear model of the 2n factorial is not significant, it is possible to design another trial based on the CCD principle to improve the model. Model improvement using build-up principle is suitable with the food industry needed, which requires fast, precise and accurate validation and verification in making decisions in terms of product development and production process.Keyword: Combination enzymes, RSM (Response Surface Method), CCD (Central Composite Design), regulation, mechanism, application.
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Siregar, Benedicta Lamria, Rexi Sebastian Siallagan, Suwarnita Butar Butar, Bambang Mahmudi e Elisabeth Sri Pujiastuti. "The Nutrient Content of Eco-enzymes from Mixture of Various Fruit Peels". Agro Bali : Agricultural Journal 7, n. 2 (31 luglio 2024): 475–87. http://dx.doi.org/10.37637/ab.v7i2.1646.
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Today, many institutions and individuals are paying attention to the development of technologies used in sustainable agriculture. One of the technologies is eco-enzyme that can be used as organic fertilizer. Several researchers have studied the use of eco-enzymes in agriculture, but studies on the nutrient content of eco-enzymes are still very limited. This research was conducted to investigate the nutrient content of two eco-enzyme preparations. The eco-enzymes were produced through the fermentation process of water, fruit peels, and molasses with a weight ratio of 10 : 3 : 1. Fruit peels used for Eco-enzyme A were banana, melon, watermelon, orange, and pineapple peels, while for Eco-enzyme B were banana, mango, watermelon, orange, and pineapple peels. The fermentation period for Eco-enzyme A was seven months, while for Eco-enzyme B was eight months. The results of the analysis showed that the two eco-enzymes contained various nutrients, both macro (C, N, P, K, Mg, Ca) and micro (Mn, Zn, B, Fe, Cu) ones, that were consistently higher in Eco-enzyme A. Both eco-enzymes were acidic, where the pH of Eco-enzyme A and B were 3.95 and 3.50, respectively. The data obtained were expected to be a basic reference for further research on eco-enzymes.
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R, Kumaravelrajan, Swetha M e Suba V. "Characterization of Immobilized β-Amylase Enzyme Isolated from Sweet Potato and prepared by Entrapment Method". International Journal of Pharmaceutical Sciences and Nanotechnology(IJPSN) 15, n. 6 (16 dicembre 2022): 6196–203. http://dx.doi.org/10.37285/ijpsn.2022.15.6.2.
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Aim: This study attempted to isolate β-amylase from sweet potato and enzyme immobilized by encapsulation method, and characterized with various parameters.
Methods: The enzyme β-amylase was isolated with phosphate-buffered saline and purified by centrifugation with ammonium sulfate. The purified enzyme was immobilized on chitosan (0.25 g) and sodium alginate (0.25 g) polymers by entrapment method in the presence of calcium chloride (0.5 M). The immobilized enzyme was characterized by a starch hydrolysis test, the optimal pH and temperature were studied and the stability of the immobilized enzyme was also determined. SEM analysis was performed and Vm and Km were also found.
Results: The starch hydrolysis test showed positive results on the starch agar plates for immobilized enzymes. The thermal inactivation showed a severe loss in the activity of the free enzymes (49.3 %) while the temperature profile of the immobilized enzymes was much broader (84.55 %) at higher temperatures (80° C). The optimal pH and stability indicated that the immobilized enzyme has higher stability in the pH range of 5-8. The Km and Vmax value of free and immobilized enzyme was 7.67 mmol, 21.15 µmol (R2 0.8880), and 4.72 mmol,16.79 µmol (R2 0.8446) respectively. The storage of free and immobilized enzymes for one month showed that 83.5 % and 40 % of free enzymes and 11.6 % and 8.6 % of immobilized enzymes lost activity at 25° C and 4° C, respectively. SEM analysis shows the smooth, porous surface.
Conclusion: Immobilized enzymes (natural polymers) exhibit higher thermal stability the optimal pH and stability indicate immobilized enzyme has higher stability in the pH range of 5-8, and achieves a relative activity of 69.7 %. After 6 uses, the reuse efficiency of the immobilized enzyme decreased from 99.8 % to 52.3 %. The storage of the immobilized enzyme showed much higher stability than the found-free enzyme.
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Vovk, H., e T. Nosenko. "Influence of enzymatic treatment parameters on the press pumkin oil yeild and its properties". Scientific Works of National University of Food Technologies 29, n. 1 (febbraio 2023): 108–18. http://dx.doi.org/10.24263/2225-2924-2023-29-1-10.
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The influence of parameters of pumpkin seeds pretreatment with enzyme preparations of proteolytic and cellulolytic activity on the yield of press oil, its composition and quality parameters were studied in this work. The enzyme preparation PENICILOPEPSIN (Enzym Biotech, Ukraine) with proteolytic activity and CELLULAD (Enzym Biotech, Ukraine) with cellulolytic, hemicellulase and xylanase activity were used for pretreatment. Enzymatic treatment of seeds was carried out with a mixture of these preparations at a ratio of 7:3 for 2 h at a pH 5.2 and 48—54°C. The following parameters of enzymatic pretreatment were studied: the amount of the enzyme mixture, which varied from 0.3% to 2.4% of the weight of the seeds and the amount of moisture added together with the enzymes — from 15% to 50%. It was established that the rational parameters of the enzymatic treatment of pumpkin seeds are the mass of the enzyme mixture of 0.6% and the amount of moisture added with enzymes — 35% of the seed mass. Under such technological parameters, the yield of press pumpkin oil was 65.6%, which is almost 6% higher than in the control sample. The acid and anisidine value of the control oil sample and the oil extracted after the enzymatic treatment of the seeds did not differ significantly. However, the content of peroxide compounds in the oil extracted after enzymatic treatment of seeds was lower. The total antioxidant activity of the oil, determined by the reaction of the 2,2-diphenyl-1- picrylhydrazyl radicals quenching within 30 min, was higher in the oil samples after seed pretreatment at the maximum tested moisture (50%). The obtained results indicate that the enzymatic pretreatment of pumpkin seeds with proteolytic and cellulolytic enzyme preparations is a promising method of oil yield increasing.
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Zhang, Song, Changping Wang, Hong Chang, Qiang Zhang e Yiyun Cheng. "Off-on switching of enzyme activity by near-infrared light-induced photothermal phase transition of nanohybrids". Science Advances 5, n. 8 (agosto 2019): eaaw4252. http://dx.doi.org/10.1126/sciadv.aaw4252.
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The off-on manipulation of enzyme activity is a challenging task. We report a new strategy for reversible off-on control of enzyme activity by near-infrared light. Enzymes acting on macromolecular substrates are embedded with an ultrasmall platinum nanoparticle and decorated with thermoresponsive copolymers, which exhibit upper critical solution temperature (UCST) behavior. The polymer-enzyme nanohybrids form microscale aggregates in solution below the UCST to prevent macromolecular substrates from approaching the enzymes and thus inhibit the enzyme activity, and they disassemble above the UCST to reactivate the enzyme. Upon near-infrared irradiation, platinum nanoparticles inside the enzymes generate heat through a photothermal effect to cause phase transition of the copolymers. Therefore, we can reversibly switch off and on the activities of three enzymes acting on polysaccharide, protein, and plasmid. The enzyme activities are increased by up to 61-fold after laser irradiation. This study provides a facile and efficient method for off-on control of enzyme activity.
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Ginting, N., e R. E. Mirwandhono. "Productivity of Turi (Sesbania grandiflora) as a multi purposes plant by eco enzyme application". IOP Conference Series: Earth and Environmental Science 912, n. 1 (1 novembre 2021): 012023. http://dx.doi.org/10.1088/1755-1315/912/1/012023.
Testo completoAbstract (sommario):
Abstract Turi (Sesbania grandiflora) is a multi-purpose plant, including leaves for animal feed, flowers for human food and wood for wood pellets. Eco enzyme is produced from the fermentation of fruits containing enzymes and organic acids. The application of Eco enzyme, among others as biocatalist to improve plant productivity. This paper aims to study dilution of Eco Enzym which was applied to Turi plants to increase its productivity This study used a completely randomized design, namely: T1: Eco enzyme dilution 1: 100; T2: 1: 200; T3: 1: 300 whereas there were 5 replications. Parameters were plant height, stem diameter, number of branches, leaf width and number of flowers. The results of this research were that the parameters of plant height, leaf of width, number of flowers had significant effect by the 1:100 dilution treatment (p<0,05). However, there was no significant effect on stem diameter and and the number of branches. The best response to eco enzyme was 1: 100.
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Fadlilla, Thanya, MTh Sri Budiastuti e MMA Retno Rosariastuti. "Potential of Fruit and Vegetable Waste as Eco-enzyme Fertilizer for Plants". Jurnal Penelitian Pendidikan IPA 9, n. 4 (30 aprile 2023): 2191–200. http://dx.doi.org/10.29303/jppipa.v9i4.3010.
Testo completoAbstract (sommario):
This study aims to determine the source of eco-enzyme raw materials and the most appropriate dilution volume to produce quality eco-enzyme fertilizer for plant growth. 1 (sugar): 3 (fruit and vegetable waste): 10 (water). The resulting eco-enzyme liquid is processed into fertilizer through the dilution process. Eco-enzyme fertilizers from each raw material source contain different organic N, P, K, and C nutrients. Besides that, some enzymes are beneficial to plants. This research is experimental in the laboratory. The experimental design was factorial design using a completely randomized design as the based design with the treatment of various sources of raw material for eco-enzyme E1 (fruit waste), E2 (vegetable waste), and E3 (fruit and vegetable waste). The parameters observed are N, P, K, and C Organic. The results showed that in terms of the quality of eco-enzyme fertilizers, the best order of eco-enzyme fertilizers was eco-enzyme fertilizer from vegetable waste (E2), eco-enzyme fertilizer from fruit and vegetable waste (E3), and eco-enzyme fertilizer from fruit waste (E1). Based on the NPK content in eco-enzyme fertilizer, eco-enzyme fertilizer is still below the quality standard for liquid organic fertilizer but the enzymes contained in eco-enzymes can also spur growth in plants.
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Galperin, Michael Y., D. Roland Walker e Eugene V. Koonin. "Analogous Enzymes: Independent Inventions in Enzyme Evolution". Genome Research 8, n. 8 (1 agosto 1998): 779–90. http://dx.doi.org/10.1101/gr.8.8.779.
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Lieberman, Jack. "Enzymes in Sarcoidosis: Angiotensin-Converting-Enzyme (ACE)". Clinics in Laboratory Medicine 9, n. 4 (dicembre 1989): 745–56. http://dx.doi.org/10.1016/s0272-2712(18)30602-4.
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Maeda, Masako. "New label enzymes for bioluminescent enzyme immunoassay". Journal of Pharmaceutical and Biomedical Analysis 30, n. 6 (gennaio 2003): 1725–34. http://dx.doi.org/10.1016/s0731-7085(02)00514-9.
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Sree Kumar, K., Yashesh N. Vaishnav e Joseph F. Weiss. "Radioprotection by antioxidant enzymes and enzyme mimetics". Pharmacology & Therapeutics 39, n. 1-3 (gennaio 1988): 301–9. http://dx.doi.org/10.1016/0163-7258(88)90076-9.
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Mebs, D., S. Mieseler, U. Rimpau, C. Vossius, B. König e S. Benesch. "Enzymes and enzyme inhibitors from marine sponges". Toxicon 33, n. 3 (marzo 1995): 304. http://dx.doi.org/10.1016/0041-0101(95)99364-9.
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Chang, Antje, Lisa Jeske, Sandra Ulbrich, Julia Hofmann, Julia Koblitz, Ida Schomburg, Meina Neumann-Schaal, Dieter Jahn e Dietmar Schomburg. "BRENDA, the ELIXIR core data resource in 2021: new developments and updates". Nucleic Acids Research 49, n. D1 (19 novembre 2020): D498—D508. http://dx.doi.org/10.1093/nar/gkaa1025.
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Abstract The BRENDA enzyme database (https://www.brenda-enzymes.org), established in 1987, has evolved into the main collection of functional enzyme and metabolism data. In 2018, BRENDA was selected as an ELIXIR Core Data Resource. BRENDA provides reliable data, continuous curation and updates of classified enzymes, and the integration of newly discovered enzymes. The main part contains >5 million data for ∼90 000 enzymes from ∼13 000 organisms, manually extracted from ∼157 000 primary literature references, combined with information of text and data mining, data integration, and prediction algorithms. Supplements comprise disease-related data, protein sequences, 3D structures, genome annotations, ligand information, taxonomic, bibliographic, and kinetic data. BRENDA offers an easy access to enzyme information from quick to advanced searches, text- and structured-based queries for enzyme-ligand interactions, word maps, and visualization of enzyme data. The BRENDA Pathway Maps are completely revised and updated for an enhanced interactive and intuitive usability. The new design of the Enzyme Summary Page provides an improved access to each individual enzyme. A new protein structure 3D viewer was integrated. The prediction of the intracellular localization of eukaryotic enzymes has been implemented. The new EnzymeDetector combines BRENDA enzyme annotations with protein and genome databases for the detection of eukaryotic and prokaryotic enzymes.
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Li, Can, Zhishang Shi, Jinxing Cai, Ping Wang, Fang Wang, Meiting Ju, Jinpeng Liu e Qilin Yu. "Synthesis of Phenylboronic Acid-Functionalized Magnetic Nanoparticles for Sensitive Soil Enzyme Assays". Molecules 27, n. 20 (14 ottobre 2022): 6883. http://dx.doi.org/10.3390/molecules27206883.
Testo completoAbstract (sommario):
Soil enzymes, such as invertase, urease, acidic phosphatase and catalase, play critical roles in soil biochemical reactions and are involved in soil fertility. However, it remains a great challenge to efficiently concentrate soil enzymes and sensitively assess enzyme activity. In this study, we synthesized phenylboronic acid-functionalized magnetic nanoparticles to rapidly capture soil enzymes for sensitive soil enzyme assays. The iron oxide magnetic nanoparticles (MNPs) were firstly prepared by the co-precipitation method and then functionalized by (3-aminopropyl)triethoxysilane, polyethyleneimine and phenylboric acid in turn, obtaining the final nanoparticles (MNPPBA). Protein-capturing assays showed that the functionalized MNPs had a much higher protein-capturing capacity than the naked MNPs (56% versus 6%). Moreover, MNPPBA almost thoroughly captured the tested enzymes, i.e., urease, invertase, and alkaline phosphatase, from enzyme solutions. Based on MNPPBA, a soil enzyme assay method was developed by integration of enzyme capture, magnetic separation and trace enzyme analysis. The method was successfully applied in determining trace enzyme activity in rhizosphere soil. This study provides a strategy to sensitively determine soil enzyme activity for mechanistic investigation of soil fertility and plant–microbiome interaction.
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Li, Jie, Xin Jin, Yang Liu, Fan Li, Linlin Zhang, Xianyuan Zhu e Yunfeng Lu. "Robust enzyme–silica composites made from enzyme nanocapsules". Chemical Communications 51, n. 47 (2015): 9628–31. http://dx.doi.org/10.1039/c5cc02053k.
Testo completoAbstract (sommario):
Novel enzyme composites are synthesized first by in situ polymerization around enzymes and a subsequent sol–gel process. Both the polymer shell and the silica shell with desired functional moieties provide not only great enzyme protection but also a favorable microenvironment, resulting in significantly enhanced activity and stability.
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Sunaga, H., H. Sugimoto, Y. Nagamachi e S. Yamashita. "Purification and properties of lysophospholipase isoenzymes from pig gastric mucosa". Biochemical Journal 308, n. 2 (1 giugno 1995): 551–57. http://dx.doi.org/10.1042/bj3080551.
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Two lysophospholipases, named gastric lysophospholipases I and II (enzymes I and II), were purified 3730- and 2680-fold from pig gastric mucosa. The preparations showed 22 and 23 kDa single protein bands on SDS/PAGE respectively. Both enzymes lacked transacylase activity and appeared to exist as monomers. Their activities were not affected by Ca2+, Mg2+ or EDTA. Enzyme I was most active at pH 8.5 and hydrolysed a variety of lysophospholipids including acidic lysophospholipids and the acyl analogue of platelet-activating factor, whereas enzyme II was most active at pH 8 and its activity was confined to lysophosphatidylcholine and lysophosphatidylethanolamine. When 1-palmitoylglycerophosphocholine was used as substrate, enzymes I and II showed half-maximal activities at 11 and 12 microM respectively. The enzymes exhibited no phospholipase B, lipase or general esterase activity. Enzyme II was significantly inhibited by lysophosphatidic acid whereas enzyme I was only moderately inhibited. Peptide mapping with V8 protease and papain revealed structural dissimilarity between the two enzymes. Antiserum raised against enzyme I did not recognize enzyme II, but did recognize the small-sized lysophospholipase purified from rat liver. Anti-(enzyme II) consistently did not cross-react with enzyme I or the liver enzyme. These antisera specifically recognized neither the 60 kDa lysophospholipase transacylase purified from liver nor any peritoneal macrophage protein. Thus gastric mucosa contains two different small-sized lysophospholipases: one is closely related to the small-sized lysophospholipase of liver, but the other appears to be a novel isoform.
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Dzulqaidah, Intan, Regina Brigita Zanuba, Andi Siti Fatimah Alwi, Arista Rizkika Putri Salsabila, Siswandi Mursidi e Handa Muliasari. "Ekstraksi dan Uji Aktivitas Enzim Bromelin Kasar dari Buah Nanas". Journal of Agritechnology and Food Processing 1, n. 2 (31 dicembre 2021): 80. http://dx.doi.org/10.31764/jafp.v1i2.6974.
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Pineapple (Ananas comosus) is a source of protease enzymes. The protease enzyme present in pineapple is the bromelain enzyme. Bromelain enzymes are widely used in various industrial fields. The purpose of this experiment was to isolate the bromelain enzyme from pineapple plants, to test the activity of the enzyme, and to determine the optimum temperature of the enzyme. Isolation of the bromelain enzyme from pineapple was carried out by precipitating the pineapple fruit filtrate using table salt (NaCl). Then the crude extract of the enzyme obtained was tested on pieces of meat with variations in the testing temperature (room temperature, hot, and cold). The yield of the crude extract of the enzyme obtained from the experiment was 40%. The results of testing the bromelain enzyme activity of pineapple showed that room temperature was the best temperature for the enzyme to tenderize meat compared to hot and cold temperatures.
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Jun, Jin-Sung, Ye-Lim You, Ha-Jun Byun, Kyung-Hoon Han, Jay Kim, Jea-Bum Jung, Hyeon-Son Choi e Sung-Hee Han. "Enzyme Activity and Lipogenesis Inhibition by Fermented Grain Using Natural Enzymes". Molecules 28, n. 21 (26 ottobre 2023): 7285. http://dx.doi.org/10.3390/molecules28217285.
Testo completoAbstract (sommario):
This study aims to compare the effects of three enzyme-rich foods, including one fermented (grain enzyme) and two non-fermented foods (enzyme foods 1 and 2), by investigating their antioxidant, anti-inflammatory, and anti-adipogenic properties. Grain enzyme exhibited the highest radical scavenging activity and was rich in antioxidant components, including total polyphenol and total flavonoid contents. Grain enzyme and enzyme foods 1 and 2 inhibited nitric oxide production by 27, 34, and 17%, respectively, at a concentration of 200 μg/mL in LPS-stimulated macrophages. Among the tested enzymes, grain enzyme demonstrated the strongest inhibition on the expression of inducible nitric oxide synthase (INOS), cyclooxygenase-2 (COX-2), and interleukin (IL)-1β, while Enzyme Food 2 exhibited the most significant suppression of IL-6 mRNA levels. Furthermore, Grain Enzyme demonstrated a stronger inhibitory effect compared to Enzyme Food 1 and 2. Grain Enzyme decreased the mRNA expression of peroxisome proliferator-activated receptor (PPAR)γ, CCAAT/enhancer-binding protein (C/EBP)α, and fatty acid-binding protein (FABP)4 by 28, 21, and 30%, respectively, at a concentration of 400 μg/mL. In summary, fermented grain enzymes outperformed non-fermented enzymes in suppressing inflammation and adipogenesis. This study highlights the anti-inflammatory and anti-adipogenic effects of grain enzyme, suggesting its potential as a valuable dietary supplement for managing metabolic disorders.
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Høst, Amalie Vang, Roberto Morellon-Sterling, Diego Carballares, John M. Woodley e Roberto Fernandez-Lafuente. "Co-Enzymes with Dissimilar Stabilities: A Discussion of the Likely Biocatalyst Performance Problems and Some Potential Solutions". Catalysts 12, n. 12 (3 dicembre 2022): 1570. http://dx.doi.org/10.3390/catal12121570.
Testo completoAbstract (sommario):
Enzymes have several excellent catalytic features, and the last few years have seen a revolution in biocatalysis, which has grown from using one enzyme to using multiple enzymes in cascade reactions, where the product of one enzyme reaction is the substrate for the subsequent one. However, enzyme stability remains an issue despite the many benefits of using enzymes in a catalytic system. When enzymes are exposed to harsh process conditions, deactivation occurs, which changes the activity of the enzyme, leading to an increase in reaction time to achieve a given conversion. Immobilization is a well-known strategy to improve many enzyme properties, if the immobilization is properly designed and controlled. Enzyme co-immobilization is a further step in the complexity of preparing a biocatalyst, whereby two or more enzymes are immobilized on the same particle or support. One crucial problem when designing and using co-immobilized enzymes is the possibility of using enzymes with very different stabilities. This paper discusses different scenarios using two co-immobilized enzymes of the same or differing stability. The effect on operational performance is shown via simple simulations using Michaelis–Menten equations to describe kinetics integrated with a deactivation term. Finally, some strategies for overcoming some of these problems are discussed.
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Pancapalaga, Wehandaka, e Endang Sri Hartati. "PELATIHAN PEMBUATAN ECO ENZYME DI PONDOK PESANTREN DAARUL FIKRI MALANG". Jurnal Pengabdian Masyarakat Bumi Raflesia 5, n. 1 (29 aprile 2022): 777–81. http://dx.doi.org/10.36085/jpmbr.v5i1.3190.
Testo completoAbstract (sommario):
Eco enzim adalah cairan serba guna hasil fermentasi selama 90 hari dari sisa buah dan sayuran yang di campur dengan gula dan air. Adapun manfaatnya untuk kesehatan manusia, pertanian dan kesehatan lingkungan. Oleh karena itu tujuan pengabdian ini adalah untuk memperkenalkan dan mensosialisasikan eco enzyme kepada siswa siswi  pondok pesantren Daarul Fikri  dalam memanfaatkan limbah disekitar pondok pesantren, selain itu untuk melatih siswa siswi pondok pesantren  membuat eco enzyme. Metode pengabdian yang digunakan berupa sosialisasi dan pelatihan pembuatan eco enzym. Metode yang digunakan secara pendidikan, pelatihan dan pendampingan. Pendidikan dalam bentuk penyuluhan tentang pentingnya eco enzyme. Pelatihan diberikan untuk  meningkatkan ketrampilan dalam hal membuat eco enzyme. Sedangkan pendampingan di khususkan bagi mereka yang sungguh sungguh mau meneruskan untuk wirausaha dengan jalan membantu dalam hal pemasaran. Evaluasi kegiatan dilakukan dengan membandingkan peningkatan persentase pengetahuan dan ketrampilan sebelum dan sesudah pelatihan membuat eco enzyme. Hasil pengabdian menunjukan bahwa Berdasarkan hasil kegiatan pelatihan di pondok Daarul fikri malang dapat disimpulkan bahwa : Pelatihan pembuatan eco enzyme dapat meningkatkan pengetahuan siswa       (152 %) dan meningkatkan ketrampilan            siswa (200 %).
26
Kopetzki, E., K. Lehnert e P. Buckel. "Enzymes in diagnostics: achievements and possibilities of recombinant DNA technology". Clinical Chemistry 40, n. 5 (1 maggio 1994): 688–704. http://dx.doi.org/10.1093/clinchem/40.5.688.
Testo completoAbstract (sommario):
Abstract We discuss, from an industrial point of view, the scope and possibilities of recombinant DNA technology for "diagnostic enzyme" production and application. We describe the construction of enzyme-overproducing strains and show how to simplify downstream processing, increase product quality and process profitability, improve diagnostic enzyme properties, and adjust enzymes to harsh assay conditions. We also consider some safety and environmental aspects of enzyme production. Other aspects of diagnostic enzymes that we cover are the facilitation of enzyme purification by attachment of short amino acid tails, the introduction of tails or tags for site-specific conjugation or oriented immobilization, the construction of bi- or multifunctional enzymes, and the production of enzyme-based diagnostic tests as demonstrated by the homogeneous immunoassay system of CEDIA tests. We use as examples of diagnostic enzymes glucose-6-phosphate dehydrogenase (EC 1.1.1.49), glucose oxidase (EC 1.1.3.4), alkaline phosphatase (EC 3.1.3.1), alpha-glucosidase (EC 3.2.1.20), pyruvate oxidase (EC 1.2.3.3), creatinase (EC 3.5.3.3), and beta-galactosidase (EC 3.2.1.23).
27
Antoun, G. R., I. Brglez e D. G. Williamson. "A 17 β-hydroxysteroid dehydrogenase of female rabbit liver cytosol. Purification and characterization of multiple forms of the enzyme". Biochemical Journal 225, n. 2 (15 gennaio 1985): 383–90. http://dx.doi.org/10.1042/bj2250383.
Testo completoAbstract (sommario):
Multiple forms of the soluble 17 beta-hydroxysteroid dehydrogenase of female rabbit liver were identified. NAD-dependent and NADP-dependent enzyme activities were separated by affinity chromatography on agarose-immobilized Procion Red HE3B, and three forms of the NADP-dependent enzyme activity were purified by chromatofocusing. These three enzyme forms are charge isomers and have no quaternary structure. The enzymes catalysed the C-17 oxidoreduction of oestrogens and androgens; with all enzyme forms the activity towards androgens was higher than that toward oestrogens. The enzymes also exhibited 3 alpha-hydroxysteroid dehydrogenase activity towards androgens of the 5 beta-androstane series. Comparison of the relative activities of the enzymes towards a number of oestrogen and androgen substrates revealed differences among the enzyme forms for both the oxidative and the reductive reactions. In particular, one enzyme form had a significantly lower Km for the 3 alpha-hydroxysteroid substrate and a higher 3 alpha-/17 beta-hydroxysteroid dehydrogenase activity ratio than the other two enzyme forms.
28
Zhu, Zheng, Song Ling, Qi-Heng Yang e Lin Li. "The Difference in the Carboxy-Terminal Sequence Is Responsible for the Difference in the Activity of Chicken and Rat Liver Fructose-2,6-Bisphosphatase". Biological Chemistry 381, n. 12 (18 dicembre 2000): 1195–202. http://dx.doi.org/10.1515/bc.2000.147.
Testo completoAbstract (sommario):
Abstract The fructose-2,6-bisphosphatase domain of the bifunctional chicken liver enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase shares approximately 95% amino acid sequence homology with that of the rat enzyme. However, these two enzymes are significantly different in their phosphatase activities. In this report, we show that the COOH-terminal 25 amino acids of the two enzymes are responsible for the different enzymatic activities. Although these 25 amino acids are not required for the phosphatase activity, their removal diminishes the differences in the activities between the two enzymes. In addition, two chimeric molecules (one consisting of the catalytic core of the chicken bisphosphatase domain and the rat COOH-terminal 25 amino acids, and the other consisting of most of the intact chicken enzyme and the rat COOH-terminal 25 amino acids) showed the same kinetic properties as the rat enzyme. Furthermore, substitution of the residues Pro456pro457Ala458 of the chicken enzyme with GluAlaGlu, the corresponding sequence in the rat liver enzyme, yields a chicken enzyme that behaves like the rat enzyme. These results demonstrate that the different bisphosphatase activities of the chicken and rat liver bifunctional enzymes can be attributed to the differences in their COOH-terminal amino acid sequences, particularly the three residues.
29
Datta, Rahul, Swati Anand, Amitava Moulick, Divyashri Baraniya, Shamina Imran Pathan, Klement Rejsek, Valerie Vranova et al. "How enzymes are adsorbed on soil solid phase and factors limiting its activity: A Review". International Agrophysics 31, n. 2 (25 aprile 2017): 287–302. http://dx.doi.org/10.1515/intag-2016-0049.
Testo completoAbstract (sommario):
Abstract A majority of biochemical reactions are often catalysed by different types of enzymes. Adsorption of the enzyme is an imperative phenomenon, which protects it from physical or chemical degradation resulting in enzyme reserve in soil. This article summarizes some of the key results from previous studies and provides information about how enzymes are adsorbed on the surface of the soil solid phase and how different factors affect enzymatic activity in soil. Many studies have been done separately on the soil enzymatic activity and adsorption of enzymes on solid surfaces. However, only a few studies discuss enzyme adsorption on soil perspective; hence, we attempted to facilitate the process of enzyme adsorption specifically on soil surfaces. This review is remarkably unmatched, as we have thoroughly reviewed the relevant publications related to protein adsorption and enzymatic activity. Also, the article focuses on two important aspects, adsorption of enzymes and factors limiting the activity of adsorbed enzyme, together in one paper. The first part of this review comprehensively lays emphasis on different interactions between enzymes and the soil solid phase and the kinetics of enzyme adsorption. In the second part, we encircle various factors affecting the enzymatic activity of the adsorbed enzyme in soil.
30
Lee, Hyeryeong, Yuna Bang e In Seop Chang. "Facilitated Enzymatic Chain Reaction-Based Bioelectrocatalysis via Solid Binding Peptide-Guided Bienzyme Co-Immobilization Strategy". ECS Meeting Abstracts MA2023-01, n. 42 (28 agosto 2023): 2357. http://dx.doi.org/10.1149/ma2023-01422357mtgabs.
Testo completoAbstract (sommario):
The multienzyme complex in biological systems are highly ordered so that intermediate molecules occurred during enzymatic sequential reaction are efficiently delivered to downstream enzymes without diffused to bulk phase. Recently, the cascadic multienzymes have been adopted to enzymatic electrocatalytic platform to be applied for enzyme-based bioelectronics such as enzyme fuel cell, biosensors, and electrosynthetic system. This cascadic enzyme-electrode, in which interfacial electron transfer (ET) occurs concurrently with inter-enzyme chain reaction, has been regarded promising for the advancement of enzyme-based bioelectronics performance. However, co-regulation of interfacial electrical connection and inter-enzyme chain reaction efficiency has been known to be highly challenging due to systematic complexity. In this context, the generalized enzyme immobilization tool is significantly needed to be developed to control inter-enzyme and enzyme-electrode interface concurrently. Herein, enzyme cascade-based direct bioelectrocatalytic system has been constructed by immobilizing enzymes using the solid binding peptide (SBP) linker that can control surface-orientation of enzymes on electrode. Here, invertase (INV) and FAD-dependent glucose dehydrogenase gamma-alpha complex (GDHγα) were utilized as upstream- and downstream enzyme so that the sucrose hydrolysis (at INV) and glucose oxidation (at GDHγα) is concomitantly occurred. Especially, the GDHγα that is direct electron transfer (DET)-capable oxidoreductase, has bi-function that are downstream catalysis and transport of produced electrons toward electrode that cause bioelectrocatalytic current signal. To immobilize enzymes and control relative orientation of coupling enzymes, the SBP linker was tethered various termini (C-, N-, or both termini) of INV when SBP fusion site of GDHγα was fixed to C-terminus of GDH α subunit to enable efficient interfacial DET, based on previous study. Therefore, the inter-enzyme relative orientation dependent chain reaction efficiency was evaluated with resulting DET-based electrocatalytic current. In the result, it was found that the interfacial DET at GDHγα-electrode could be affected by binding conformation of co-immobilized enzyme, fusion INV. Most importantly, the chain reaction efficiency between INV and GDHγα was revealed to be diverse depending on different relative orientation determined by SBP tethering sites in enzymes. The intermediate delivery route was changed by relative positioning of coupling active sites, affecting overall cascade reaction rate. Taking into account the factors related with interfacial DET and intermediate delivery, precise design of bienzymatic electrode is indeed necessary in order to introduce SBP-tethering technique to cascadic enzyme-derived direct electrocatalytic platform. Figure 1
31
Vannoy, Kathryn J., Andrey Ryabykh, Andrei I. Chapoval e Jeffrey E. Dick. "Single enzyme electroanalysis". Analyst 146, n. 11 (2021): 3413–21. http://dx.doi.org/10.1039/d1an00230a.
Testo completoAbstract (sommario):
Traditional enzymology relies on the kinetics of millions of enzymes, an experimental approach that may wash out heterogeneities between individual enzymes. Electrochemical methods have emerged in the last 5 years to probe single enzyme reactivity.
32
Mirzaei, Mitra, e Per Berglund. "Engineering of ωTransaminase for Effective Production of Chiral Amines". Journal of Computational and Theoretical Nanoscience 17, n. 6 (1 giugno 2020): 2827–32. http://dx.doi.org/10.1166/jctn.2020.8947.
Testo completoAbstract (sommario):
ωTransaminases are pyridoxal-5-phosphat (PLP) dependent enzymes having the ability to catalyze the transference of an amino group to a keto compound. These enzymes are used for production of chiral amines which are important building blocks in pharmaceutical industry. There is often a need to improve enzyme properties such as enzyme stability, enzyme specificity and to decrease substrate-product inhibition. Here, protein engineering was applied to improve the enzyme activity of the enzyme from Chromobacterium violaceum Rational-design and site-directed mutagenesis were applied on position of (W60) in the active site of the enzyme. Different mutated enzyme variants such as W60H, W60F and W60Y were made. Also, the enantiopreference of the wild type enzyme was reversed to produce (R)-chiral amines. For this aim, a screening assay was followed by semi-rational approach and saturation mutagenesis in the active site of the enzyme. Creating the mutated enzyme libraries resulted to obtaining two enzyme variants. Their properties were low enantiopreference towards formations of (R)-enantiopreference and low specific constant ratio between fast and slow enantiomers (Evalue around one).
33
Szczepanowski, Roman H., Renata Filipek e Matthias Bochtler. "Crystal Structure of a Fragment of Mouse Ubiquitin-activating Enzyme". Journal of Biological Chemistry 280, n. 23 (16 marzo 2005): 22006–11. http://dx.doi.org/10.1074/jbc.m502583200.
Testo completoAbstract (sommario):
Protein ubiquitination requires the sequential activity of three enzymes: a ubiquitin-activating enzyme (E1), a ubiquitin-conjugating enzyme (E2), and a ubiquitin-ligase (E3). The ubiquitin-transfer machinery is hierarchically organized; for every ubiquitin-activating enzyme, there are several ubiquitin-conjugating enzymes, and most ubiquitin-conjugating enzymes can in turn interact with multiple ubiquitin ligases. Despite the central role of ubiquitin-activating enzyme in this cascade, a crystal structure of a ubiquitin-activating enzyme is not available. The enzyme is thought to consist of an adenylation domain, a catalytic cysteine domain, a four-helix bundle, and possibly, a ubiquitin-like domain. Its adenylation domain can be modeled because it is clearly homologous to the structurally known adenylation domains of the activating enzymes for the small ubiquitin-like modifier (SUMO) and for the protein encoded by the neuronal precursor cell-expressed, developmentally down-regulated gene 8 (NEDD8). Low sequence similarity and vastly different domain lengths make modeling difficult for the catalytic cysteine domain that results from the juxtaposition of two catalytic cysteine half-domains. Here, we present a biochemical and crystallographic characterization of the two half-domains and the crystal structure of the larger, second catalytic cysteine half-domain of mouse ubiquitin-activating enzyme. We show that the domain is organized around a conserved folding motif that is also present in the NEDD8- and SUMO-activating enzymes, and we propose a tentative model for full-length ubiquitin-activating enzyme.
34
Hickey, A. M., L. Marle, T. McCreedy, P. Watts, G. M. Greenway e J. A. Littlechild. "Immobilization of thermophilic enzymes in miniaturized flow reactors". Biochemical Society Transactions 35, n. 6 (23 novembre 2007): 1621–23. http://dx.doi.org/10.1042/bst0351621.
Testo completoAbstract (sommario):
The exploitation of enzymes for biotransformation reactions for the production of new and safer drug intermediates has been the focus of much research. While a number of enzymes are commercially available, their use in an industrial setting is often limited to reactions that are cost-effective and they are rarely investigated further. However, the development of miniaturized flow reactor technology has meant that the cost of such research, once considered cost- and time-inefficient, would be much less prohibitive. The use of miniaturized flow reactors for enzyme screening offers a number of advantages over batch enzyme assay systems. Since the assay is performed on a miniaturized scale, enzyme, substrate and cofactor quantities are significantly reduced, thus reducing the cost of laboratory-scale investigations. Since flow reactors use microfluidic systems, where the substrate and products flow out of the system, the problems of substrate inhibition and product inhibition encountered by some enzymes are avoided. Quite often, enzymes fulfil a single-use function in biotransformation processes; however, enzyme immobilization allows enzyme reuse and often helps to increase enzyme stability. We have used an aminoacylase enzyme with potential use for industrial biotransformation reactions and have successfully immobilized it in miniaturized flow reactors. This L-aminoacylase is from the thermophilic archaeon Thermococcus litoralis. Two approaches to enzyme immobilization have been examined, both involving enzyme cross-linking. The first reactor type has used monoliths, to which the enzyme was attached, and the second contained previously cross-linked enzyme trapped using frits, in the microfluidic channels. Two different microreactor designs were used in the investigation: microreactor chips for the monoliths and capillary flow reactors for the cross-linked enzyme. These systems allowed passage of the substrate and product through the system while retaining the aminoacylase enzyme performing the catalytic conversion. The enzyme has been successfully immobilized and used to produce stable biocatalytic microreactors that can be used repeatedly over a period of several months.
35
Ahmad, Raneem, Jordan Shanahan, Sydnie Rizaldo, Daniel S. Kissel e Kari L. Stone. "Co-immobilization of an Enzyme System on a Metal-Organic Framework to Produce a More Effective Biocatalyst". Catalysts 10, n. 5 (2 maggio 2020): 499. http://dx.doi.org/10.3390/catal10050499.
Testo completoAbstract (sommario):
In many respects, enzymes offer advantages over traditional chemical processes due to their decreased energy requirements for function and inherent greener processing. However, significant barriers exist for the utilization of enzymes in industrial processes due to their limited stabilities and inability to operate over larger temperature and pH ranges. Immobilization of enzymes onto solid supports has gained attention as an alternative to traditional chemical processes due to enhanced enzymatic performance and stability. This study demonstrates the co-immobilization of glucose oxidase (GOx) and horseradish peroxidase (HRP) as an enzyme system on Metal-Organic Frameworks (MOFs), UiO-66 and UiO-66-NH2, that produces a more effective biocatalyst as shown by the oxidation of pyrogallol. The two MOFs utilized as solid supports for immobilization were chosen to investigate how modifications of the MOF linker affect stability at the enzyme/MOF interface and subsequent activity of the enzyme system. The enzymes work in concert with activation of HRP through the addition of glucose as a substrate for GOx. Enzyme immobilization and leaching studies showed HRP/GOx@UiO-66-NH2 immobilized 6% more than HRP/GOx@UiO-66, and leached only 36% of the immobilized enzymes over three days in the solution. The enzyme/MOF composites also showed increased enzyme activity in comparison with the free enzyme system: the composite HRP/GOx@UiO-66-NH2 displayed 189 U/mg activity and HRP/GOx@UiO-66 showed 143 U/mg while the free enzyme showed 100 U/mg enzyme activity. This increase in stability and activity is due to the amine group of the MOF linker in HRP/GOx@UiO-66-NH2 enhancing electrostatic interactions at the enzyme/MOF interface, thereby producing the most stable biocatalyst material in solution. The HRP/GOx@UiO-66-NH2 also showed long-term stability in the solid state for over a month at room temperature.
36
Gakhar, Lokesh, Zulfiqar A. Malik, Christopher C. R. Allen, David A. Lipscomb, Michael J. Larkin e S. Ramaswamy. "Structure and Increased Thermostability of Rhodococcus sp. Naphthalene 1,2-Dioxygenase". Journal of Bacteriology 187, n. 21 (1 novembre 2005): 7222–31. http://dx.doi.org/10.1128/jb.187.21.7222-7231.2005.
Testo completoAbstract (sommario):
ABSTRACT Rieske nonheme iron oxygenases form a large class of aromatic ring-hydroxylating dioxygenases found in microorganisms. These enzymes enable microorganisms to tolerate and even exclusively utilize aromatic compounds for growth, making them good candidates for use in synthesis of chiral intermediates and bioremediation. Studies of the chemical stability and thermostability of these enzymes thus become important. We report here the structure of free and substrate (indole)-bound forms of naphthalene dioxygenase from Rhodococcus sp. strain NCIMB12038. The structure of the Rhodococcus enzyme reveals that, despite a ∼30% sequence identity between these naphthalene dioxygenases, their overall structures superpose very well with a root mean square deviation of less than 1.6 Å. The differences in the active site of the two enzymes are pronounced near the entrance; however, indole binds to the Rhodococcus enzyme in the same orientation as in the Pseudomonas enzyme. Circular dichroism spectroscopy experiments show that the Rhodococcus enzyme has higher thermostability than the naphthalene dioxygenase from Pseudomonas species. The Pseudomonas enzyme has an apparent melting temperature of 55°C while the Rhodococcus enzyme does not completely unfold even at 95°C. Both enzymes, however, show similar unfolding behavior in urea, and the Rhodococcus enzyme is only slightly more tolerant to unfolding by guanidine hydrochloride. Structure analysis suggests that the higher thermostability of the Rhodococcus enzyme may be attributed to a larger buried surface area and extra salt bridge networks between the α and β subunits in the Rhodococcus enzyme.
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Pratiwi, Nurma, e Sigit Ardiansyah. "UTILIZATION OF AGRICULTURAL WASTE AS A SUBSTRATE FOR PRODUCING CELLULASE ENZYME BY ASPERGILLUS NIGER". Jurnal Pengembangan Agroindustri Terapan 1, n. 1 (12 settembre 2022): 23–30. http://dx.doi.org/10.25181/jupiter.v1i1.2655.
Testo completoAbstract (sommario):
Fresh Fruit Bunches (FFB) of oil palm, bran, straw, and bagasse are agricultural wastes whose availability is very abundant in Indonesia. The agricultural waste is lignocellulosic waste which still has economic value if further processing is carried out, namely as a substrate in the production of cellulase enzymes. Cellulase enzymes are commonly used in various industries such as food biotechnology, textiles, animal feed, paper, and agriculture to degrade cellulose with its main products, namely glucose, cellobiose, and cellooligosaccharides. In producing cellulase enzymes, it is necessary to have microorganisms that have a high ability to produce enzymes, one of which is Aspergillus niger. The purpose of this study was to determine the activity of crude cellulase enzyme, protein content, and specific activity of cellulase enzyme from agricultural waste which includes FFB, bran, straw, and bagasse. The research methods included preparation of Aspergillus niger culture, delignification, basal medium preparation, cellulase enzyme production, enzyme extraction, crude cellulase enzyme activity test (CMC-ase), lowry method protein content test, and determination of cellulase enzyme specific activity. The study showed that the highest crude cellulase enzyme activity in bran was 26.83 U/ml, the highest protein content in bagasse was 63.42 g/ml, and the highest specific activity of cellulase enzyme in straw was 0.9818 U/ml. The high enzyme activity is influenced by the cellulose content in the material, type of substrate, media, substrate concentration, pH, and temperature.
38
Antoun, G. R., e D. G. Williamson. "Age-dependent changes in the multiple forms of the soluble 17 β-hydroxysteroid dehydrogenase of female rabbit liver". Biochemical Journal 225, n. 2 (15 gennaio 1985): 391–98. http://dx.doi.org/10.1042/bj2250391.
Testo completoAbstract (sommario):
The soluble NADP-dependent 17 beta-hydroxysteroid dehydrogenase activity of female rabbit liver increases with the age of the animal, the specific activity of the enzyme in the 56-day-old rabbit being 3 times that of the 28-day-old animal. The increase in activity is accompanied by a change in the molecular heterogeneity of the enzyme. Three forms (enzymes I, II and III) were identified in the liver cytosol of the 56-day-old female rabbit, whereas only one major form (enzyme IIIY) was present in the 28-day-old animal. Peptide maps of the four purified enzymes showed that there were minor differences in structure. The enzyme present in the liver of the 28-day-old rabbit was distinct from the three enzymes of the 56-day-old animal. All of the enzymes exhibited bifunctional activity, having 17 beta-hydroxysteroid dehydrogenase activity towards androgen and oestrogen substrates and 3 alpha-hydroxysteroid dehydrogenase activity towards androgens of the 5 beta-androstane series. The differences in substrate specificity of the enzymes paralleled their differences in structure. The data suggest that one enzyme (enzyme III) may have a special role in steroid metabolism during development in the female rabbit.
39
Lin, Peng, Hui Yang, Eiji Nakata e Takashi Morii. "Mechanistic Aspects for the Modulation of Enzyme Reactions on the DNA Scaffold". Molecules 27, n. 19 (24 settembre 2022): 6309. http://dx.doi.org/10.3390/molecules27196309.
Testo completoAbstract (sommario):
Cells have developed intelligent systems to implement the complex and efficient enzyme cascade reactions via the strategies of organelles, bacterial microcompartments and enzyme complexes. The scaffolds such as the membrane or protein in the cell are believed to assist the co-localization of enzymes and enhance the enzymatic reactions. Inspired by nature, enzymes have been located on a wide variety of carriers, among which DNA scaffolds attract great interest for their programmability and addressability. Integrating these properties with the versatile DNA–protein conjugation methods enables the spatial arrangement of enzymes on the DNA scaffold with precise control over the interenzyme distance and enzyme stoichiometry. In this review, we survey the reactions of a single type of enzyme on the DNA scaffold and discuss the proposed mechanisms for the catalytic enhancement of DNA-scaffolded enzymes. We also review the current progress of enzyme cascade reactions on the DNA scaffold and discuss the factors enhancing the enzyme cascade reaction efficiency. This review highlights the mechanistic aspects for the modulation of enzymatic reactions on the DNA scaffold.
40
Lee, Sun Hyung, Ji Sook Lim e Han Seung Kim. "Decomposition of Chlorinated Hydrocarbons Using the Biocatalyst Immobilized by Clay Minerals". Advanced Materials Research 356-360 (ottobre 2011): 1089–92. http://dx.doi.org/10.4028/www.scientific.net/amr.356-360.1089.
Testo completoAbstract (sommario):
Biochemical decomposition of catechol and 4-chlorocatechol, degradation intermediate products of 4-chlorophenol, was investigated using enzymes and their immobilized forms by clay minerals. An oxygenase that can initiate oxidative ring-fission of aromatic compounds was obtained via cloning of its gene (cphA-1) encoding hydroxyquinol dioxygenase contained in Arthrobacter chlorophenolicus A6 and overexpression and purification of the enzyme. The enzyme expressed in vitro was then immobilized onto the clay mineral (montmorillonite). Michaelis-Menten kinetic analysis was conducted to compare the expressed enzymes and the immobilized biocatalysts with regard to their degradation activity and capability to sustain activities under severe environments. Vmax values for the immobilized enzymes were smaller than those for the originally cloned enzymes, indicating that loss of enzyme activity was accompanied in the enzyme immobilization process. However, the immobilized enzyme demonstrated far more stable degrading activity in response to wide environmental changes such as marked variation of pH, temperature, and ionic strength. This supported that the enzyme immobilization can provide great advantages for its field application and also should be useful for establishing the concept of ecological green U-City.
41
Vanderstocken, Gilles, Nicholas L. Woolf, Giuseppe Trigiante, Jessica Jackson e Rory McGoldrick. "Harnessing the Potential of Enzymes as Inhaled Therapeutics in Respiratory Tract Diseases: A Review of the Literature". Biomedicines 10, n. 6 (17 giugno 2022): 1440. http://dx.doi.org/10.3390/biomedicines10061440.
Testo completoAbstract (sommario):
Respiratory tract diseases (RTDs) are a global cause of mortality and affect patient well-being and quality of life. Specifically, there is a high unmet need concerning respiratory tract infections (RTIs) due to limitations of vaccines and increased antibiotic resistance. Enzyme therapeutics, and in particular plant-based enzymes, represent an underutilised resource in drug development warranting further attention. This literature review aims to summarise the current state of enzyme therapeutics in medical applications, with a focus on their potential to improve outcomes in RTDs, including RTIs. We used a narrative review approach, searching PubMed and clinicaltrials.gov with search terms including: enzyme therapeutics, enzyme therapy, inhaled therapeutics, botanical enzyme therapeutics, plant enzymes, and herbal extracts. Here, we discuss the advantages and challenges of enzyme therapeutics in the setting of RTDs and identify and describe several enzyme therapeutics currently used in the respiratory field. In addition, the review includes recent developments concerning enzyme therapies and plant enzymes in (pre-)clinical stages. The global coronavirus disease 2019 (COVID-19) pandemic has sparked development of several promising new enzyme therapeutics for use in the respiratory setting, and therefore, it is timely to provide a summary of recent developments, particularly as these therapeutics may also prove beneficial in other RTDs.
42
O'Keefe, S. J., W. M. Bennet, A. R. Zinsmeister e M. W. Haymond. "Pancreatic enzyme synthesis and turnover in human subjects". American Journal of Physiology-Gastrointestinal and Liver Physiology 266, n. 5 (1 maggio 1994): G816—G821. http://dx.doi.org/10.1152/ajpgi.1994.266.5.g816.
Testo completoAbstract (sommario):
Animal studies have shown that pancreatic enzyme secretion is independent of enzyme synthesis. To investigate this relationship in humans, we have coinfused 14C-labeled leucine tracer with cholecystokinin octapeptide in nine healthy adults for 4 h and measured the rate of appearance of secreted and newly labeled enzymes in the duodenum. Enzyme secretion was well maintained throughout, but newly labeled enzymes only appeared in juice between 75 and 101 min (median time, 86 min), indicating that initial secretion was dependent on the release of zymogen stores and that the median production time for new enzymes was 86 min. Between 85 and 225 min there was a curvilinear increase in the enrichment of secreted enzymes with newly synthesized enzymes, suggesting a median turnover rate of zymogen stores of 29%/h (range 12-47%/h). In conclusion, our results suggest that in healthy humans, postprandial pancreatic enzyme secretion is maintained by the export of a large stored pool and is not rate limited by enzyme synthesis, since it takes approximately 86 min for newly synthesized enzymes to take part in the digestive process.
43
Patel*, Kaushal, e Jyoti Kumawat. "Study the Dynamic Behavior of the Enzyme-Substrate Reaction using Mathematical Modeling". Biosciences Biotechnology Research Asia 20, n. 3 (5 ottobre 2023): 1047–53. http://dx.doi.org/10.13005/bbra/3155.
Testo completoAbstract (sommario):
ABSTRACT: Physiological reaction plays a vital role in the human body. These reactions are analysed through Enzyme kinetics using a Mathematical model which helps to predict how enzymes behave in living organisms. However, many factors affect the working mechanism of biocatalysts (Enzymes). Chemical denaturant creates high disruption to the structure of enzyme with time. The determination of enzyme activities with time delivers information on enzyme parameters. Here the analysis aims to mathematical study for the development of Enzyme - substrates reaction for product formation based on time. So we formulate the model as a system of nonlinear differential equations which predicts the behaviour of product formation based on Enzyme- Substrate reaction parameters. Compute the threshold value for studying the enzyme effectiveness, complexity, and other parameters for the substrate product. Study the stability analysis for the ideal product formation and hence derive asymptotically stable solutions for the Enzyme- Substrate model with numerical simulation.
44
Pyne, N. J., M. E. Cooper e M. D. Houslay. "Identification and characterization of both the cytosolic and particulate forms of cyclic GMP-stimulated cyclic AMP phosphodiesterase from rat liver". Biochemical Journal 234, n. 2 (1 marzo 1986): 325–34. http://dx.doi.org/10.1042/bj2340325.
Testo completoAbstract (sommario):
Two enzymes displaying cyclic GMP-stimulated cyclic AMP phosphodiesterase activity were purified from rat liver to apparent homogeneity: a ‘particulate enzyme’ found as an integral membrane protein associated with the plasma membrane, and a ‘soluble’ enzyme found in the cytosol. The physical properties of these enzymes were very similar, being dimers of Mr 134,000, composed in each instance of two subunits of Mr = 66,000-67,000. Both enzymes showed similar kinetics for cyclic AMP hydrolysis. They are both high-affinity enzymes, with kinetic constants for the particulate enzyme of Km = 34 microM and Vmax. = 4.0 units/mg of protein and for the cytosolic enzyme Km = 40 microM and Vmax. = 4.8 units/mg of protein. In both instances hydrolysis of cyclic AMP appeared to show apparent positive co-operativity, with Hill coefficients (happ.) of 1.5 and 1.6 for the particulate and cytosolic enzymes respectively. However, in the presence of 2 microM-cyclic GMP, the hydrolysis of cyclic AMP obeyed Michaelis kinetics (happ. = 1) for both enzymes. The addition of micromolar concentrations of cyclic GMP had little effect on the Vmax. for cyclic AMP hydrolysis, but lowered the Km for cyclic AMP hydrolysis to around 20 microM in both cases. However, at low cyclic AMP substrate concentrations, cyclic GMP was a more potent activator of the particulate enzyme than was the soluble enzyme. The activity of these enzymes could be selectively inhibited by cis-16-palmitoleic acid and by arachidonic acid. In each instance, however, the hydrolysis of cyclic AMP became markedly more sensitive to such inhibition when low concentrations of cyclic GMP were present. Tryptic peptide maps of iodinated preparations of these two purified enzyme species showed that there was considerable homology between these two enzyme forms.
45
Zharare, Tafadzwa, e Rumbidzai Mangoyi. "Isolation and Activity Determination of Enzyme Phosphatase Secreted by Aspergillus niger". International Annals of Science 9, n. 1 (16 novembre 2019): 41–45. http://dx.doi.org/10.21467/ias.9.1.41-45.
Testo completoAbstract (sommario):
The use of enzymes on industrial scale saves a lot of energy and avoids pollution, thus holding a promise for green and economically sustainable alternative strategies in industrial transformations. Generally, the fungi Aspergillus niger secretes enzymes which can be used in different industries. Thus, coming up with these enzymes in large amounts will definitely result in reduced costs encountered in importing them for industrial use. This study focussed on isolation and activity determination of an enzyme phosphatase secreted by Aspergillus niger. This enzyme can be of great importance in molecular biology industries, particularly for recombinant DNA technology. For this study, pure cultures of Aspergillus niger were used. Aspergillus niger was resuscitated on potato dextrose agar and then subcultured in Adam’s medium, a medium specific for the production of phosphatase. Cells were centrifuged and the filtrate was collected whilst the residue was discarded. The filtrate was expected to contain the crude enzyme phosphatase since Aspergillus niger secretes the extracellular enzyme into the medium. Disodium phenyl phosphate was used as a substrate for the determination of the phosphatase activity. The enzyme activity was determined spectrophotometrically by reading absorbance of phenol formed in the presence of enzyme and the substrate. The concentration of phenol liberated was then used to calculate the enzyme activity expressed in King Armstrong Units (KAU). Further work on enzyme activity determination was done by varying enzyme and substrate concentrations. Results showed that the isolated alkaline phosphatase had activity of 4.0 KAU and 4.5 KAU at 25 ºC and 37 ºC respectively. Acidic phosphatase had activity of 5 KAU and 7 KAU at 25 ºC and 37 ºC respectively. Rate of activity increased upon increasing enzyme concentration and substrate. Thus, Aspergillus niger produces the enzyme phosphatase, however, there is need to induce the production of these enzymes for industrial use.
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Alfiyanti, Retno Dewi, Berlian Prihatiningrum e Roedy Budirahardjo. "The Efek Enzim Bromelin Buah Nanas (Ananas comosus (L.) Merr) Berbasis Sediaan Gel terhadap Lebar Intertubulus Dentin". Pustaka Kesehatan 7, n. 3 (25 ottobre 2020): 195. http://dx.doi.org/10.19184/pk.v7i3.11705.
Testo completoAbstract (sommario):
Caries tissue cleaning can use Chemo-Mechanical Caries Removal (CMCR) based on proteolytic enzymes that catalyze peptide bonds into simpler compounds. Proteolytic enzymes can be found in mature pineapple bromelain enzymes. The aim of the study is to determine the effect of gel-based bromelain enzyme with concentrations of 8%, 10% and 12% against the width of the intertubulus dentin. The bromelain enzyme is extracted using the Lowry method. Then purified using 80% ethanol and diluting become to concentrations of 8%, 10% and 12%. Diluted bromelain enzymes were formed in gel preparations based on HPMC and applied to the study sample. The results of this study indicated a widening of the intertubulus dentin. This is indicated by the variation of the dentin intertubulus width > 2µm. This widening occurs because the bromelain enzyme can hydrolyze collagen in intertubulus dentin in the absence of alpha-l-antitrypsin. Hydrolysis causes the breaking of hydrogen bonds in the triple helix- shaped tropocollagen to turn into strands of polypeptide chains. The bromelain enzyme with a concentration 10% is more effective than 8% and 12% because it is within the maximum speed limit of the enzyme so that the enzyme is saturated by its substrate and there is a difference in specific enzyme activity in each concentration.
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Li, B. F. L., D. Holdup, C. A. J. Morton e M. L. Sinnott. "The catalytic consequences of experimental evolution. Transition-state structure during catalysis by the evolved β-galactosidases of Escherichia coli (ebg enzymes) changed by a single mutational event". Biochemical Journal 260, n. 1 (15 maggio 1989): 109–14. http://dx.doi.org/10.1042/bj2600109.
Testo completoAbstract (sommario):
1. The first chemical step in the hydrolysis of galactosylpyridinium ions by the evolvant ebg enzyme is less sensitive to leaving-group acidity than in the case of the wild-type ebg enzyme, implying less glycone-aglycone-bond fission at the transition state. 2. The first chemical step in the hydrolysis of aryl galactosides by ebg enzyme is probably less sensitive to leaving-group acidity than in the case of ebg enzyme, possibly as a consequence of resulting in more effective proton donation to the leaving aglycone. 3. alpha-Deuterium kinetic isotope effects of 1.1(0) and beta-deuterium kinetic isotope effects of 1.0(0) were measured for the hydrolysis of galactosyl-enzyme intermediates derived from ebg and ebg enzymes: these effects are not compatible with reaction of the sugar ring through a 4C1-like conformation, or with an ionic glycosyl-enzyme intermediate. 4. The variation with pH of steady-state kinetic parameters for hydrolysis of p-nitrophenyl galactoside by ebg and ebg enzymes and of 3-methylphenyl beta-galactoside, 3,4-dinitrophenyl beta-galactoside and beta-galactosyl-3-bromopyridinium ion by ebg enzyme was measured. The steep, non-classical, fall in activity against p-nitrophenyl galactoside at low pH observed with ebg and ebg enzymes is not observed with ebg enzymes.
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Yu, Tianhao, Haiyang Cui, Jianan Canal Li, Yunan Luo, Guangde Jiang e Huimin Zhao. "Enzyme function prediction using contrastive learning". Science 379, n. 6639 (31 marzo 2023): 1358–63. http://dx.doi.org/10.1126/science.adf2465.
Testo completoAbstract (sommario):
Enzyme function annotation is a fundamental challenge, and numerous computational tools have been developed. However, most of these tools cannot accurately predict functional annotations, such as enzyme commission (EC) number, for less-studied proteins or those with previously uncharacterized functions or multiple activities. We present a machine learning algorithm named CLEAN (contrastive learning–enabled enzyme annotation) to assign EC numbers to enzymes with better accuracy, reliability, and sensitivity compared with the state-of-the-art tool BLASTp. The contrastive learning framework empowers CLEAN to confidently (i) annotate understudied enzymes, (ii) correct mislabeled enzymes, and (iii) identify promiscuous enzymes with two or more EC numbers—functions that we demonstrate by systematic in silico and in vitro experiments. We anticipate that this tool will be widely used for predicting the functions of uncharacterized enzymes, thereby advancing many fields, such as genomics, synthetic biology, and biocatalysis.
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Mokhtar, Nur Fathiah, Raja Noor Zaliha Raja Abd. Rahman, Noor Dina Muhd Noor, Fairolniza Mohd Shariff e Mohd Shukuri Mohamad Ali. "The Immobilization of Lipases on Porous Support by Adsorption and Hydrophobic Interaction Method". Catalysts 10, n. 7 (4 luglio 2020): 744. http://dx.doi.org/10.3390/catal10070744.
Testo completoAbstract (sommario):
Four major enzymes commonly used in the market are lipases, proteases, amylases, and cellulases. For instance, in both academic and industrial levels, microbial lipases have been well studied for industrial and biotechnological applications compared to others. Immobilization is done to minimize the cost. The improvement of enzyme properties enables the reusability of enzymes and facilitates enzymes used in a continuous process. Immobilized enzymes are enzymes physically confined in a particularly defined region with retention to their catalytic activities. Immobilized enzymes can be used repeatedly compared to free enzymes, which are unable to catalyze reactions continuously in the system. Immobilization also provides a higher pH value and thermal stability for enzymes toward synthesis. The main parameter influencing the immobilization is the support used to immobilize the enzyme. The support should have a large surface area, high rigidity, suitable shape and particle size, reusability, and resistance to microbial attachment, which will enhance the stability of the enzyme. The diffusion of the substrate in the carrier is more favorable on hydrophobic supports instead of hydrophilic supports. The methods used for enzyme immobilization also play a crucial role in immobilization performance. The combination of immobilization methods will increase the binding force between enzymes and the support, thus reducing the leakage of the enzymes from the support. The adsorption of lipase on a hydrophobic support causes the interfacial activation of lipase during immobilization. The adsorption method also causes less or no change in enzyme conformation, especially on the active site of the enzyme. Thus, this method is the most used in the immobilization process for industrial applications.
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Sulaiman, Nurul Jannah, e Roshanida Abd Rahman. "New Advancement on Cross-Linked Enzyme Aggregates within Magnetically-Separable Mesoporous Silica". Applied Mechanics and Materials 818 (gennaio 2016): 276–80. http://dx.doi.org/10.4028/www.scientific.net/amm.818.276.
Testo completoAbstract (sommario):
Magnetically-separable enzyme system has been developed by adsorption, precipitation and cross-linking of enzymes in superparamagnetic hierarchically ordered mesoporous mesocellular silica (M-HMMS). The immobilization of xylanase within M-HMMS were compared between enzyme adsorption (EA), enzyme adsorption and cross-linking (EAC), and enzyme adsorption, precipitation and cross-linking (EAPC). EAPC includes higher enzyme activity immobilized within the matrix in comparison with the other methods. Furthermore, the immobilized enzyme is predicted to be prevented from leaching out of the matrix when exterior blow is being tested on the structure. Thus, the stability of the EAPC of this invention is anticipated to be maintained even after a long time passed since high enzyme activity compared with known method can be supported and immobilized within the matrix. Consequently, it is possible to improve performance of the enzymes by manipulating the preparation and operation condition.