Journal articles: 'Β-galactosidases'

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Kumar, Vijay, Nikhil Sharma, and Tek Chand Bhalla. "In Silico Analysis of β-Galactosidases Primary and Secondary Structure in relation to Temperature Adaptation." Journal of Amino Acids 2014 (March 24, 2014): 1–9. http://dx.doi.org/10.1155/2014/475839.

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β-D-Galactosidases (EC 3.2.1.23) hydrolyze the terminal nonreducing β-D-galactose residues in β-D-galactosides and are ubiquitously present in all life forms including extremophiles. Eighteen microbial β-galactosidase protein sequences, six each from psychrophilic, mesophilic, and thermophilic microbes, were analyzed. Primary structure reveals alanine, glycine, serine, and arginine to be higher in psychrophilic β-galactosidases whereas valine, glutamine, glutamic acid, phenylalanine, threonine, and tyrosine are found to be statistically preferred by thermophilic β-galactosidases. Cold active β-galactosidase has a strong preference towards tiny and small amino acids, whereas high temperature inhabitants had higher content of basic and aromatic amino acids. Thermophilic β-galactosidases have higher percentage of α-helix region responsible for temperature tolerance while cold loving β-galactosidases had higher percentage of sheet and coil region. Secondary structure analysis revealed that charged and aromatic amino acids were significant for sheet region of thermophiles. Alanine was found to be significant and high in the helix region of psychrophiles and valine counters in thermophilic β-galactosidase. Coil region of cold active β-galactosidase has higher content of tiny amino acids which explains their high catalytic efficiency over their counterparts from thermal habitat. The present study has revealed the preference or prevalence of certain amino acids in primary and secondary structure of psychrophilic, mesophilic, and thermophilic β-galactosidase.

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Møller, Peter L., Flemming Jørgensen, Ole C. Hansen, Søren M. Madsen, and Peter Stougaard. "Intra- and Extracellular β-Galactosidases fromBifidobacterium bifidum and B. infantis: Molecular Cloning, Heterologous Expression, and Comparative Characterization." Applied and Environmental Microbiology 67, no. 5 (May 1, 2001): 2276–83. http://dx.doi.org/10.1128/aem.67.5.2276-2283.2001.

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ABSTRACT Three β-galactosidase genes from Bifidobacterium bifidum DSM20215 and one β-galactosidase gene fromBifidobacterium infantis DSM20088 were isolated and characterized. The three B. bifidum β-galactosidases exhibited a low degree of amino acid sequence similarity to each other and to previously published β-galactosidases classified as family 2 glycosyl hydrolases. Likewise, the B. infantisβ-galactosidase was distantly related to enzymes classified as family 42 glycosyl hydrolases. One of the enzymes from B. bifidum, termed BIF3, is most probably an extracellular enzyme, since it contained a signal sequence which was cleaved off during heterologous expression of the enzyme in Escherichia coli. Other exceptional features of the BIF3 β-galactosidase were (i) the monomeric structure of the active enzyme, comprising 1,752 amino acid residues (188 kDa) and (ii) the molecular organization into an N-terminal β-galactosidase domain and a C-terminal galactose binding domain. The other two B. bifidumβ-galactosidases and the enzyme from B. infantis were multimeric, intracellular enzymes with molecular masses similar to typical family 2 and family 42 glycosyl hydrolases, respectively. Despite the differences in size, molecular composition, and amino acid sequence, all four β-galactosidases were highly specific for hydrolysis of β-d-galactosidic linkages, and all four enzymes were able to transgalactosylate with lactose as a substrate.

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Pressey, Russell, and C. M. Sean Carrington. "β-Galactosidase II in Ripening Tomatoes." HortScience 30, no. 4 (July 1995): 817A—817. http://dx.doi.org/10.21273/hortsci.30.4.817a.

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Tomatoes contain several isozymes of β-galactosidase, but only one, β-galactosidase II, can hydrolyze the β-1,4-galactans in tomato cell walls. β-galactosidase II has now been highly purified by modification of the original procedure. The molecular weight of this isozyme is ≈62 kDa according to gel infiltration, but SDS-PAGE of the purified enzyme separated three components with molecular weights of 29, 42, and 82 kDa. The 82-kDa peptide may be the intact enzyme and the smallest peptides are subunits as proposed for other β-galactosidases. The N-terminal amino acid sequence of β-galactosidase II showed high homology with amino acid sequences reported for other plant β-galactosidases. A new assay for β-galactosidase II in tomato extracts has been developed using FPLC. This isozyme was not detected in mature-green tomatoes but appeared at about the breaker stage and increased during ripening. The increase in b-galactosidase II was accompanied by a decrease in galactose content of cell wall polysaccharides, suggesting that this enzyme may be involved in the loss of galactose during tomato ripening.

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Núñez-Montero, Kattia, Rodrigo Salazar, Andrés Santos, Olman Gómez-Espinoza, Scandar Farah, Claudia Troncoso, Catalina Hoffmann, Damaris Melivilu, Felipe Scott, and Leticia Barrientos Díaz. "Antarctic Rahnella inusitata: A Producer of Cold-Stable β-Galactosidase Enzymes." International Journal of Molecular Sciences 22, no. 8 (April 16, 2021): 4144. http://dx.doi.org/10.3390/ijms22084144.

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There has been a recent increase in the exploration of cold-active β-galactosidases, as it offers new alternatives for the dairy industry, mainly in response to the current needs of lactose-intolerant consumers. Since extremophilic microbial compounds might have unique physical and chemical properties, this research aimed to study the capacity of Antarctic bacterial strains to produce cold-active β-galactosidases. A screening revealed 81 out of 304 strains with β-galactosidase activity. The strain Se8.10.12 showed the highest enzymatic activity. Morphological, biochemical, and molecular characterization based on whole-genome sequencing confirmed it as the first Rahnella inusitata isolate from the Antarctic, which retained 41–62% of its β-galactosidase activity in the cold (4 °C–15 °C). Three β-galactosidases genes were found in the R. inusitata genome, which belong to the glycoside hydrolase families GH2 (LacZ and EbgA) and GH42 (BglY). Based on molecular docking, some of these enzymes exhibited higher lactose predicted affinity than the commercial control enzyme from Aspergillus oryzae. Hence, this work reports a new Rahnella inusitata strain from the Antarctic continent as a prominent cold-active β-galactosidase producer.

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Eda, Masahiro, Megumi Ishimaru, and Toshiji Tada. "Expression, purification, crystallization and preliminary X-ray crystallographic analysis of tomato β-galactosidase 4." Acta Crystallographica Section F Structural Biology Communications 71, no. 2 (January 28, 2015): 153–56. http://dx.doi.org/10.1107/s2053230x14027800.

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Plant β-galactosidases play important roles in carbohydrate-reserve mobilization, cell-wall expansion and degradation, and turnover of signalling molecules during ripening. Tomato β-galactosidase 4 (TBG4) not only has β-galactosidase activity but also has exo-β-(1,4)-galactanase activity, and prefers β-(1,4)-galactans longer than pentamers as its substrates; most other β-galactosidases only have the former activity. Recombinant TBG4 protein expressed in the yeastPichia pastoriswas crystallized by the sitting-drop vapour-diffusion method using PEG 10 000 as a precipitant. The crystals belonged to the orthorhombic space groupP212121, with unit-parametersa= 92.82,b= 96.30,c= 159.26 Å, and diffracted to 1.65 Å resolution. Calculation of the Matthews coefficient suggested the presence of two monomers per asymmetric unit (VM= 2.2 Å3 Da−1), with a solvent content of 45%.

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Dutra Rosolen, Michele, Adriano Gennari, Giandra Volpato, and Claucia Fernanda Volken de Souza. "Lactose Hydrolysis in Milk and Dairy Whey Using Microbial β-Galactosidases." Enzyme Research 2015 (October 26, 2015): 1–7. http://dx.doi.org/10.1155/2015/806240.

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This work aimed at evaluating the influence of enzyme concentration, temperature, and reaction time in the lactose hydrolysis process in milk, cheese whey, and whey permeate, using two commercial β-galactosidases of microbial origins. We used Aspergillus oryzae (at temperatures of 10 and 55°C) and Kluyveromyces lactis (at temperatures of 10 and 37°C) β-galactosidases, both in 3, 6, and 9 U/mL concentrations. In the temperature of 10°C, the K. lactis β-galactosidase enzyme is more efficient in the milk, cheese whey, and whey permeate lactose hydrolysis when compared to A. oryzae. However, in the enzyme reaction time and concentration conditions evaluated, 100% lactose hydrolysis was not reached using the K. lactis β-galactosidase. The total lactose hydrolysis in whey and permeate was obtained with the A. oryzae enzyme, when using its optimum temperature (55°C), at the end of a 12 h reaction, regardless of the enzyme concentration used. For the lactose present in milk, this result occurred in the concentrations of 6 and 9 U/mL, with the same time and temperature conditions. The studied parameters in the lactose enzymatic hydrolysis are critical for enabling the application of β-galactosidases in the food industry.

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Ferreira-Lazarte, Alvaro, F. Javier Moreno, and Mar Villamiel. "Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management." Food & Function 9, no. 9 (2018): 4642–50. http://dx.doi.org/10.1039/c8fo01091a.

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Strategies to avoid lactose malabsorption, which affects 70% of the world's population, are focused on the restriction of milk and dairy products or the use of non-human β-galactosidases or probiotics endowed with β-galactosidase activity added at mealtime.

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Pham, Mai-Lan, Anh-Minh Tran, Suwapat Kittibunchakul, Tien-Thanh Nguyen, Geir Mathiesen, and Thu-Ha Nguyen. "Immobilization of β-Galactosidases on the Lactobacillus Cell Surface Using the Peptidoglycan-Binding Motif LysM." Catalysts 9, no. 5 (May 12, 2019): 443. http://dx.doi.org/10.3390/catal9050443.

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Lysin motif (LysM) domains are found in many bacterial peptidoglycan hydrolases. They can bind non-covalently to peptidoglycan and have been employed to display heterologous proteins on the bacterial cell surface. In this study, we aimed to use a single LysM domain derived from a putative extracellular transglycosylase Lp_3014 of Lactobacillus plantarum WCFS1 to display two different lactobacillal β-galactosidases, the heterodimeric LacLM-type from Lactobacillus reuteri and the homodimeric LacZ-type from Lactobacillus delbrueckii subsp. bulgaricus, on the cell surface of different Lactobacillus spp. The β-galactosidases were fused with the LysM domain and the fusion proteins, LysM-LacLMLreu and LysM-LacZLbul, were successfully expressed in Escherichia coli and subsequently displayed on the cell surface of L. plantarum WCFS1. β-Galactosidase activities obtained for L. plantarum displaying cells were 179 and 1153 U per g dry cell weight, or the amounts of active surface-anchored β-galactosidase were 0.99 and 4.61 mg per g dry cell weight for LysM-LacLMLreu and LysM-LacZLbul, respectively. LysM-LacZLbul was also displayed on the cell surface of other Lactobacillus spp. including L. delbrueckii subsp. bulgaricus, L. casei and L. helveticus, however L. plantarum is shown to be the best among Lactobacillus spp. tested for surface display of fusion LysM-LacZLbul, both with respect to the immobilization yield as well as the amount of active surface-anchored enzyme. The immobilized fusion LysM-β-galactosidases are catalytically efficient and can be reused for several repeated rounds of lactose conversion. This approach, with the β-galactosidases being displayed on the cell surface of non-genetically modified food-grade organisms, shows potential for applications of these immobilized enzymes in the synthesis of prebiotic galacto-oligosaccharides.

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Rutkiewicz-Krotewicz, Maria, Agnieszka J. Pietrzyk-Brzezinska, Bartosz Sekula, Hubert Cieśliński, Anna Wierzbicka-Woś, Józef Kur, and Anna Bujacz. "Structural studies of a cold-adapted dimeric β-D-galactosidase fromParacoccussp. 32d." Acta Crystallographica Section D Structural Biology 72, no. 9 (August 31, 2016): 1049–61. http://dx.doi.org/10.1107/s2059798316012535.

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The crystal structure of a novel dimeric β-D-galactosidase fromParacoccussp. 32d (ParβDG) was solved in space groupP212121at a resolution of 2.4 Å by molecular replacement with multiple models using theBALBESsoftware. This enzyme belongs to glycoside hydrolase family 2 (GH2), similar to the tetrameric and hexameric β-D-galactosidases fromEscherichia coliandArthrobactersp. C2-2, respectively. It is the second known structure of a cold-active GH2 β-galactosidase, and the first in the form of a functional dimer, which is also present in the asymmetric unit. Cold-adapted β-D-galactosidases have been the focus of extensive research owing to their utility in a variety of industrial technologies. One of their most appealing applications is in the hydrolysis of lactose, which not only results in the production of lactose-free dairy, but also eliminates the `sandy effect' and increases the sweetness of the product, thus enhancing its quality. The determined crystal structure represents the five-domain architecture of the enzyme, with its active site located in close vicinity to the dimer interface. To identify the amino-acid residues involved in the catalytic reaction and to obtain a better understanding of the mechanism of action of this atypical β-D-galactosidase, the crystal structure in complex with galactose (ParβDG–Gal) was also determined. The catalytic site of the enzyme is created by amino-acid residues from the central domain 3 and from domain 4 of an adjacent monomer. The crystal structure of this dimeric β-D-galactosidase reveals significant differences in comparison to other β-galactosidases. The largest difference is in the fifth domain, named Bgal_windup domain 5 inParβDG, which contributes to stabilization of the functional dimer. The location of this domain 5, which is unique in size and structure, may be one of the factors responsible for the creation of a functional dimer and cold-adaptation of this enzyme.

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Thoma, Julia, David Stenitzer, Reingard Grabherr, and Erika Staudacher. "Identification, Characterization, and Expression of a β-Galactosidase from Arion Species (Mollusca)." Biomolecules 12, no. 11 (October 27, 2022): 1578. http://dx.doi.org/10.3390/biom12111578.

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β-Galactosidases (β-Gal, EC 3.2.1.23) catalyze the cleavage of terminal non-reducing β-D-galactose residues or transglycosylation reactions yielding galacto-oligosaccharides. In this study, we present the isolation and characterization of a β-galactosidase from Arion lusitanicus, and based on this, the cloning and expression of a putative β-galactosidase from Arion vulgaris (A0A0B7AQJ9) in Sf9 cells. The entire gene codes for a protein consisting of 661 amino acids, comprising a putative signal peptide and an active domain. Specificity studies show exo- and endo-cleavage activity for galactose β1,4-linkages. Both enzymes, the recombinant from A. vulgaris and the native from A. lusitanicus, display similar biochemical parameters. Both β-galactosidases are most active in acidic environments ranging from pH 3.5 to 4.5, and do not depend on metal ions. The ideal reaction temperature is 50 °C. Long-term storage is possible at up to +4 °C for the A. vulgaris enzyme, and at up to +20 °C for the A. lusitanicus enzyme. This is the first report of the expression and characterization of a mollusk exoglycosidase.

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Eberhardt, María Florencia, José Matías Irazoqui, and Ariel Fernando Amadio. "β-Galactosidases from a Sequence-Based Metagenome: Cloning, Expression, Purification and Characterization." Microorganisms 9, no. 1 (December 28, 2020): 55. http://dx.doi.org/10.3390/microorganisms9010055.

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Stabilization ponds are a common treatment technology for wastewater generated by dairy industries. Large proportions of cheese whey are thrown into these ponds, creating an environmental problem because of the large volume produced and the high biological and chemical oxygen demands. Due to its composition, mainly lactose and proteins, it can be considered as a raw material for value-added products, through physicochemical or enzymatic treatments. β-Galactosidases (EC 3.2.1.23) are lactose modifying enzymes that can transform lactose in free monomers, glucose and galactose, or galactooligosacharides. Here, the identification of novel genes encoding β-galactosidases, identified via whole-genome shotgun sequencing of the metagenome of dairy industries stabilization ponds is reported. The genes were selected based on the conservation of catalytic domains, comparing against the CAZy database, and focusing on families with β-galactosidases activity (GH1, GH2 and GH42). A total of 394 candidate genes were found, all belonging to bacterial species. From these candidates, 12 were selected to be cloned and expressed. A total of six enzymes were expressed, and five cleaved efficiently ortho-nitrophenyl-β-galactoside and lactose. The activity levels of one of these novel β-galactosidase was higher than other enzymes reported from functional metagenomics screening and higher than the only enzyme reported from sequence-based metagenomics. A group of novel mesophilic β-galactosidases from diary stabilization ponds’ metagenomes was successfully identified, cloned and expressed. These novel enzymes provide alternatives for the production of value-added products from dairy industries’ by-products.

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Binz, Thomas, Colette Gremaud, and Giorgio Canevascini. "Production and purification of an extracellular β-galactosidase from the Dutch elm disease fungus Ophiostoma novo-ulmi." Canadian Journal of Microbiology 43, no. 11 (November 1, 1997): 1011–16. http://dx.doi.org/10.1139/m97-146.

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The causal agents of Dutch elm disease, Ophiostoma ulmi (isolate H200) and Ophiostoma novo-ulmi (isolate CKT-11), secreted similar amounts of β-galactosidase in liquid shake cultures when grown on galacturonic acid or sodium pectate (1.45 ± 0.16 and 1.03 ± 0.24 nkat∙mL−1 for O. ulmi, respectively, and 1.30 ± 0.08 and 1.28 ± 0.26 nkat∙mL−1 for O. novo-ulmi, respectively). Rhamnose and pectin also stimulated secretion but to a lesser extent, whereas on glucose, enzyme activity was barely detectable (≤0.01 nkat∙mL−1). Ophiostoma novo-ulmi was shown by Q-Sepharose chromatography to form two β-galactosidases, named β-galactosidases I and II. In cultures grown on galacturonic acid β-galactosidase I accounted for approximately 75% of the total activity in the culture filtrate. β-Galactosidase I was further purified to apparent electrophoretic homogeneity by means of Sephacryl gel filtration chromatography, chromatofocusing, and Superdex75 gel filtration. The molecular mass of the enzyme was 135 kDa by SDS–PAGE and 123 kDa by gel filtration. Its isoelectric point, determined by chromatofocusing, was 4.9. The optimal pH for enzyme activity was 5.8 and the optimal temperature was 50 °C. The Km values for p-nitrophenyl β-D-galactopyranoside and lactose were 7.52 and 14.23 mM, respectively, and the maximum velocities for these substrates were 1733 and 355 nkat∙mg protein−1, respectively. The Ki value for D(−)-galactonic acid γ-lactone was 2.29 mM.Key words: Dutch elm disease, β-galactosidase, Ophiostoma ulmi, Ophiostoma novo-ulmi.

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ŽIBRAT, Nika, Mihaela SKRT, and Polona JAMNIK. "Uporaba β-galaktozidaze na področju živilstva in prehrane." Acta agriculturae Slovenica 110, no. 1 (October 5, 2017): 5. http://dx.doi.org/10.14720/aas.2017.110.1.1.

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β-galactosidase is an enzyme with hydrolytic and transgalactosylation activity. The origin of the enzyme dictates the balance between both activities. Industrially used β-galactosidases are obtained with recombinant production from filamentus funghi <em>Aspergillus</em> sp. and yeasts <em>Kluyveromyces</em> sp. Recently thermostabile β-galactosidases have been subject of many research. The enzyme can be industrially used in free or immobilized form. Immobilization often provides better stability, reusability and lower expenses. Application of β-galactosidase is most common in food processing and nutrition, it is also used in medicine and ecology. Hydrolytic activity of the enzyme has long been used for reducing lactose content in milk, while transgalactosylitic activity is used for synthesis of products such as galactooligosaccharides, lactosucrose and others. The latter have a great potential in food industry for obtaining products with reduced lactose content and increasing of nutritional value by adding dietetic fibers such as galactooligosaccharides. Despite the potential it is vital that reaction mechanisms become better understood and optimization is in place in order to reach the usability of this enzyme at industrial level.

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Nibbering, Pieter, Bent L. Petersen, Mohammed Saddik Motawia, Bodil Jørgensen, Peter Ulvskov, and Totte Niittylä. "Golgi-localized exo-β1,3-galactosidases involved in cell expansion and root growth in Arabidopsis." Journal of Biological Chemistry 295, no. 31 (June 3, 2020): 10581–92. http://dx.doi.org/10.1074/jbc.ra120.013878.

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Plant arabinogalactan proteins (AGPs) are a diverse group of cell surface– and wall–associated glycoproteins. Functionally important AGP glycans are synthesized in the Golgi apparatus, but the relationships among their glycosylation levels, processing, and functionalities are poorly understood. Here, we report the identification and functional characterization of two Golgi-localized exo-β-1,3-galactosidases from the glycosyl hydrolase 43 (GH43) family in Arabidopsis thaliana. GH43 loss-of-function mutants exhibited root cell expansion defects in sugar-containing growth media. This root phenotype was associated with an increase in the extent of AGP cell wall association, as demonstrated by Yariv phenylglycoside dye quantification and comprehensive microarray polymer profiling of sequentially extracted cell walls. Characterization of recombinant GH43 variants revealed that the exo-β-1,3-galactosidase activity of GH43 enzymes is hindered by β-1,6 branches on β-1,3-galactans. In line with this steric hindrance, the recombinant GH43 variants did not release galactose from cell wall–extracted glycoproteins or AGP-rich gum arabic. These results indicate that the lack of exo-β-1,3-galactosidase activity alters cell wall extensibility in roots, a phenotype that could be explained by the involvement of galactosidases in AGP glycan biosynthesis.

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Moroz, Olga V., Elena Blagova, Andrey A. Lebedev, Filomeno Sánchez Rodríguez, Daniel J. Rigden, Jeppe Wegener Tams, Reinhard Wilting, et al. "Multitasking in the gut: the X-ray structure of the multidomain BbgIII from Bifidobacterium bifidum offers possible explanations for its alternative functions." Acta Crystallographica Section D Structural Biology 77, no. 12 (November 17, 2021): 1564–78. http://dx.doi.org/10.1107/s2059798321010949.

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β-Galactosidases catalyse the hydrolysis of lactose into galactose and glucose; as an alternative reaction, some β-galactosidases also catalyse the formation of galactooligosaccharides by transglycosylation. Both reactions have industrial importance: lactose hydrolysis is used to produce lactose-free milk, while galactooligosaccharides have been shown to act as prebiotics. For some multi-domain β-galactosidases, the hydrolysis/transglycosylation ratio can be modified by the truncation of carbohydrate-binding modules. Here, an analysis of BbgIII, a multidomain β-galactosidase from Bifidobacterium bifidum, is presented. The X-ray structure has been determined of an intact protein corresponding to a gene construct of eight domains. The use of evolutionary covariance-based predictions made sequence docking in low-resolution areas of the model spectacularly easy, confirming the relevance of this rapidly developing deep-learning-based technique for model building. The structure revealed two alternative orientations of the CBM32 carbohydrate-binding module relative to the GH2 catalytic domain in the six crystallographically independent chains. In one orientation the CBM32 domain covers the entrance to the active site of the enzyme, while in the other orientation the active site is open, suggesting a possible mechanism for switching between the two activities of the enzyme, namely lactose hydrolysis and transgalactosylation. The location of the carbohydrate-binding site of the CBM32 domain on the opposite site of the module to where it comes into contact with the catalytic GH2 domain is consistent with its involvement in adherence to host cells. The role of the CBM32 domain in switching between hydrolysis and transglycosylation modes offers protein-engineering opportunities for selective β-galactosidase modification for industrial purposes in the future.

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Mine, Shouhei, and Masahiro Watanabe. "Structural Insights into the Molecular Evolution of the Archaeal Exo-β-d-Glucosaminidase." International Journal of Molecular Sciences 20, no. 10 (May 18, 2019): 2460. http://dx.doi.org/10.3390/ijms20102460.

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The archaeal exo-β-d-glucosaminidase (GlmA), a thermostable enzyme belonging to the glycosidase hydrolase (GH) 35 family, hydrolyzes chitosan oligosaccharides into monomer glucosamines. GlmA is a novel enzyme in terms of its primary structure, as it is homologous to both GH35 and GH42 β-galactosidases. The catalytic mechanism of GlmA is not known. Here, we summarize the recent reports on the crystallographic analysis of GlmA. GlmA is a homodimer, with each subunit comprising three distinct domains: a catalytic TIM-barrel domain, an α/β domain, and a β1 domain. Surprisingly, the structure of GlmA presents features common to GH35 and GH42 β-galactosidases, with the domain organization resembling that of GH42 β-galactosidases and the active-site architecture resembling that of GH35 β-galactosidases. Additionally, the GlmA structure also provides critical information about its catalytic mechanism, in particular, on how the enzyme can recognize glucosamine. Finally, we postulate an evolutionary pathway based on the structure of an ancestor GlmA to extant GH35 and GH42 β-galactosidases.

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Liburdi, Katia, and Marco Esti. "Galacto-Oligosaccharide (GOS) Synthesis during Enzymatic Lactose-Free Milk Production: State of the Art and Emerging Opportunities." Beverages 8, no. 2 (April 2, 2022): 21. http://dx.doi.org/10.3390/beverages8020021.

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Much attention has recently been paid to β-Galactosidases (β-D-galactoside galactohidrolase; EC 3.2.1.23), commonly known as lactases, due to the lactose intolerance of the human population and the importance of dairy products in the human diet. This enzyme, produced by microorganisms, is being used in the dairy industry for hydrolyzing the lactose found in milk to produce lactose-free milk (LFM). Conventionally, β-galactosidases catalyze the hydrolysis of lactose to produce glucose and galactose in LFM; however, they can also catalyze transgalactosylation reactions that produce a wide range of galactooligosaccharides (GOS), which are functional prebiotic molecules that confer health benefits to human health. In this field, different works aims to identify novel microbial sources of β-galactosidase for removing lactose from milk with the relative GOS production. Lactase extracted from thermophilic microorganisms seems to be more suitable for the transgalactosylation process at relatively high temperatures, as it inhibits microbial contamination. Different immobilization methods, such as adsorption, covalent attachment, chemical aggregation, entrapment and micro-encapsulation, have been used to synthesize lactose-derived oligosaccharides with immobilized β-galactosidases. In this mini-review, particular emphasis has been given to the immobilization techniques and bioreactor configurations developed for GOS synthesis in milk, in order to provide a more detailed overview of the biocatalytic production of milk oligosaccharides at industrial level.

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Singh, M. B., and R. B. Knox. "β-Galactosidases of Lilium pollen." Phytochemistry 24, no. 8 (January 1985): 1639–43. http://dx.doi.org/10.1016/s0031-9422(00)82526-1.

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Morozova, A. N., A. E. Akhremchuk, and N. А. Golovnyova. "Мolecular-genetic analysis of determinants encoding β-galactosidases of bacteria Bifidobacterium longum BIM B-813 D." Proceedings of the National Academy of Sciences of Belarus, Biological Series 67, no. 3 (August 2, 2022): 274–84. http://dx.doi.org/10.29235/1029-8940-2022-67-3-274-284.

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The molecular-genetic analysis of the bacterial genome of the strain B. longum BIM B-813D distinguished by a high level of β-galactosidase production was performed. Genes Bgal_small_N, lacZ1, bgaB1, bgaB2 and bgaB3, and lacZ2, encoding the synthesis of β-galactosidases, were revealed in the deciphered genome. It was shown that the genes lacZ1, bgaB2, and bgaB3 characterized by an enhanced degree of similarity to the genes of closely related bifidobacterial species, presumably code for the enzymes catalyzing the specific reactions of hydrolysis and transglycosylation of carbohydrates. It was found that the enzymes BgaB1, BgaB2 and BgaB3 belong to the GH42 family of glycosyl hydrolases, whereas the enzymes LacZ1 and LacZ2 – to the GH2 family. The genome domains responsible for the synthesis of β-galactosidases in the strain B. longum BIM B-813D were studied in detail. A comparative analysis of the locus of lacZ1 in B. longum BIM B-813D and the similar genome fragment AS143_01230 from B. longum subsp. longum MC-42 detected the presence of the transposase gene ISL3 in the former strain. It was suggested that the insertion of the sequence of ISL3 in the lacZ1 locus resulted in the modified gene expression and the increased production of β-galactosidase in the strain B. longum BIM B-813D.

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Mangiagalli, Marco, and Marina Lotti. "Cold-Active β-Galactosidases: Insight into Cold Adaptation Mechanisms and Biotechnological Exploitation." Marine Drugs 19, no. 1 (January 19, 2021): 43. http://dx.doi.org/10.3390/md19010043.

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β-galactosidases (EC 3.2.1.23) catalyze the hydrolysis of β-galactosidic bonds in oligosaccharides and, under certain conditions, transfer a sugar moiety from a glycosyl donor to an acceptor. Cold-active β-galactosidases are identified in microorganisms endemic to permanently low-temperature environments. While mesophilic β-galactosidases are broadly studied and employed for biotechnological purposes, the cold-active enzymes are still scarcely explored, although they may prove very useful in biotechnological processes at low temperature. This review covers several issues related to cold-active β-galactosidases, including their classification, structure and molecular mechanisms of cold adaptation. Moreover, their applications are discussed, focusing on the production of lactose-free dairy products as well as on the valorization of cheese whey and the synthesis of glycosyl building blocks for the food, cosmetic and pharmaceutical industries.

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Arsov, Alexander, Ivan Ivanov, Lidia Tsigoriyna, Kaloyan Petrov, and Penka Petrova. "In Vitro Production of Galactooligosaccharides by a Novel β-Galactosidase of Lactobacillus bulgaricus." International Journal of Molecular Sciences 23, no. 22 (November 18, 2022): 14308. http://dx.doi.org/10.3390/ijms232214308.

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β-galactosidase is an enzyme with dual activity and important industrial application. As a hydrolase, the enzyme eliminates lactose in milk, while as a trans-galactosidase it produces prebiotic galactooligosaccharides (GOS) with various degrees of polymerization (DP). The aim of the present study is the molecular characterization of β-galactosidase from a Bulgarian isolate, Lactobacillus delbrueckii subsp. bulgaricus 43. The sequencing of the β-gal gene showed that it encodes a new enzyme with 21 amino acid replacements compared to all other β-galactosidases of this species. The molecular model revealed that the new β-galactosidase acts as a tetramer. The amino acids D207, H386, N464, E465, Y510, E532, H535, W562, N593, and W980 form the catalytic center and interact with Mg2+ ions and substrate. The β-gal gene was cloned into a vector allowing heterologous expression of E. coli BL21(DE3) with high efficiency, as the crude enzyme reached 3015 U/mL of the culture or 2011 U/mg of protein. The enzyme’s temperature optimum at 55 °C, a pH optimum of 6.5, and a positive influence of Mg2+, Mn2+, and Ca2+ on its activity were observed. From lactose, β-Gal produced a large amount of GOS with DP3 containing β-(1→3) and β-(1→4) linkages, as the latter bond is particularly atypical for the L. bulgaricus enzymes. DP3-GOS formation was positively affected by high lactose concentrations. The process of lactose conversion was rapid, with a 34% yield of DP3-GOS in 6 h, and complete degradation of 200 g/L of lactose for 12 h. On the other hand, the enzyme was quite stable at 55 °C and retained about 20% of its activity after 24 h of incubation at this temperature. These properties expand our horizons as regards the use of β-galactosidases in industrial processes for the production of lactose-free milk and GOS-enriched foods.

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Wang, He, Ruijin Yang, Xiaoyan Jiang, Xiao Hua, Wei Zhao, Wenbin Zhang, and Xuan Chen. "Expression and Characterization of Two β-Galactosidases from Klebsiella pneumoniae 285 in Escherichia coli and their Application in the Enzymatic Synthesis of Lactulose and 1-Lactulose." Zeitschrift für Naturforschung C 69, no. 11-12 (December 1, 2014): 479–87. http://dx.doi.org/10.5560/znc.2014-0061.

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Abstract The two genes lacZ1 and lacZ2 from Klebsiella pneumoniae 285, encoding β-galactosidase isoenzymes II and III (KpBGase-II and -III), were each cloned downstream of a T7 promoter for expression in Escherichia coli BL21(DE3), and the resulting recombinant enzymes were characterized in detail. The optimum temperature and pH value of KpBGase-II were 40 °C and 7.5, and those of KpBGase-III were 50 °C and 8.0, respectively. KpBGase-III was more stable than KpBGase-II at higher temperature (>60°C). Both β-galactosidases were more active towards o-nitrophenyl-β- D-galactopyranoside as compared to lactose. The enzymatic synthesis of lactulose and 1-lactulose catalyzed by KpBGase-II and KpBGase-III was investigated. Using 400 g/L lactose and 200 g/L fructose as substrates, the resulting lactulose and 1-lactulose yields with KpBGase-II were 6.2 and 42.3 g/L, while those with KpBGase-III were 5.1 and 23.8 g/L, respectively. KpBGase-II has a potential for the production of 1-lactulose from lactose and fructose. Like other β-galactosidases, the two isozymes catalyze the transgalactosylation in the presence of fructose establishing the β-(1→1) linkage.

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Mulualem, Daniel Mehabie, Christy Agbavwe, Lesley A. Ogilvie, Brian V. Jones, Michelle Kilcoyne, Conor O’Byrne, and Aoife Boyd. "Metagenomic identification, purification and characterisation of the Bifidobacterium adolescentis BgaC β-galactosidase." Applied Microbiology and Biotechnology 105, no. 3 (January 11, 2021): 1063–78. http://dx.doi.org/10.1007/s00253-020-11084-y.

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AbstractMembers of the human gut microbiota use glycoside hydrolase (GH) enzymes, such as β-galactosidases, to forage on host mucin glycans and dietary fibres. A human faecal metagenomic fosmid library was constructed and functionally screened to identify novel β-galactosidases. Out of the 16,000 clones screened, 30 β-galactosidase-positive clones were identified. The β-galactosidase gene found in the majority of the clones was BAD_1582 from Bifidobacterium adolescentis, subsequently named bgaC. This gene was cloned with a hexahistidine tag, expressed in Escherichia coli and His-tagged-BgaC was purified using Ni2+-NTA affinity chromatography and size filtration. The enzyme had optimal activity at pH 7.0 and 37 °C, with a wide range of pH (4–10) and temperature (0–40 °C) stability. It required a divalent metal ion co-factor; maximum activity was detected with Mg2+, while Cu2+ and Mn2+ were inhibitory. Kinetic parameters were determined using ortho-nitrophenyl-β-d-galactopyranoside (ONPG) and lactose substrates. BgaC had a Vmax of 107 μmol/min/mg and a Km of 2.5 mM for ONPG and a Vmax of 22 μmol/min/mg and a Km of 3.7 mM for lactose. It exhibited low product inhibition by galactose with a Ki of 116 mM and high tolerance for glucose (66% activity retained in presence of 700 mM glucose). In addition, BgaC possessed transglycosylation activity to produce galactooligosaccharides (GOS) from lactose, as determined by TLC and HPLC analysis. The enzymatic characteristics of B. adolescentis BgaC make it an ideal candidate for dairy industry applications and prebiotic manufacture.Key points• Bifidobacterium adolescentis BgaC β-galactosidase was selected from human faecal metagenome.• BgaC possesses sought-after properties for biotechnology, e.g. low product inhibition.• BgaC has transglycosylation activity producing prebiotic oligosaccharides.

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Shipkowski, Stephanie, and Jean E. Brenchley. "Bioinformatic, Genetic, and Biochemical Evidence that Some Glycoside Hydrolase Family 42 β-Galactosidases Are Arabinogalactan Type I Oligomer Hydrolases." Applied and Environmental Microbiology 72, no. 12 (October 20, 2006): 7730–38. http://dx.doi.org/10.1128/aem.01306-06.

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ABSTRACT Glycoside hydrolases are organized into glycoside hydrolase families (GHFs) and within this larger group, the β-galactosidases are members of four families: 1, 2, 35, and 42. Most genes encoding GHF 42 enzymes are from prokaryotes unlikely to encounter lactose, suggesting a different substrate for these enzymes. In search of this substrate, we analyzed genes neighboring GHF 42 genes in databases and detected an arrangement implying that these enzymes might hydrolyze oligosaccharides released by GHF 53 enzymes from arabinogalactan type I, a pectic plant polysaccharide. Because Bacillus subtilis has adjacent GHF 42 and GHF 53 genes, we used it to test the hypothesis that a GHF 42 enzyme (LacA) could act on the oligosaccharides released by a GHF 53 enzyme (GalA) from galactan. We cloned these genes, plus a second GHF 42 gene from B. subtilis, yesZ, into Escherichia coli and demonstrated that cells expressing LacA with GalA gained the ability to use galactan as a carbon source. We constructed B. subtilis mutants and showed that the increased β-galactosidase activity generated in response to the addition of galactan was eliminated by inactivating lacA or galA but unaffected by the inactivation of yesZ. As further demonstration, we overexpressed the LacA and GalA proteins in E. coli and demonstrated that these enzymes degrade galactan in vitro as assayed by thin-layer chromatography. Our work provides the first in vivo evidence for a function of some GHF 42 β-galactosidases. Similar functions for other β-galactosidases in both GHFs 2 and 42 are suggested by genomic data.

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Coombs, Jonna, and Jean E. Brenchley. "Characterization of Two New Glycosyl Hydrolases from the Lactic Acid Bacterium Carnobacterium piscicolaStrain BA." Applied and Environmental Microbiology 67, no. 11 (November 1, 2001): 5094–99. http://dx.doi.org/10.1128/aem.67.11.5094-5099.2001.

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ABSTRACT Three genes with homology to glycosyl hydrolases were detected on a DNA fragment cloned from a psychrophilic lactic acid bacterium isolate,Carnobacterium piscicola strain BA. A 2.2-kb region corresponding to an α-galactosidase gene, agaA, was followed by two genes in the same orientation, bgaB, encoding a 2-kb β-galactosidase, and bgaC, encoding a structurally distinct 1.76-kb β-galactosidase. This gene arrangement had not been observed in other lactic acid bacteria, including Lactococcus lactis, for which the genome sequence is known. To determine if these sequences encoded enzymes with α- and β-galactosidase activities, we subcloned the genes and examined the enzyme properties. The α-galactosidase, AgaA, hydrolyzespara-nitrophenyl-α-d-galactopyranoside and has optimal activity at 32 to 37°C. The β-galactosidase, BgaC, has an optimal activity at 40°C and a half-life of 15 min at 45°C. The regulation of these enzymes was tested in C. piscicolastrain BA and activity on both α- and β-galactoside substrates decreased for cells grown with added glucose or lactose. Instead, an increase in activity on a phosphorylated β-galactoside substrate was found for the cells supplemented with lactose, suggesting that a phospho-galactosidase functions during lactose utilization. Thus, the two β-galactosidases may act synergistically with the α-galactosidase to degrade other polysaccharides available in the environment.

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KISO, Taro, Hirofumi NAKANO, Hirofumi NAKAJIMA, Tadamasa TERAI, Katsuyuki OKAMOTO, and Sumio KITAHATA. "Hydrolysis of β-Galactosyl Ester Linkage by β-Galactosidases." Bioscience, Biotechnology, and Biochemistry 64, no. 8 (January 2000): 1702–6. http://dx.doi.org/10.1271/bbb.64.1702.

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de Vries, Ronald P., Hetty C. van den Broeck, Ester Dekkers, Paloma Manzanares, Leo H. de Graaff, and Jaap Visser. "Differential Expression of Three α-Galactosidase Genes and a Single β-Galactosidase Gene from Aspergillus niger." Applied and Environmental Microbiology 65, no. 6 (June 1, 1999): 2453–60. http://dx.doi.org/10.1128/aem.65.6.2453-2460.1999.

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ABSTRACT A gene encoding a third α-galactosidase (AglB) fromAspergillus niger has been cloned and sequenced. The gene consists of an open reading frame of 1,750 bp containing six introns. The gene encodes a protein of 443 amino acids which contains a eukaryotic signal sequence of 16 amino acids and seven putative N-glycosylation sites. The mature protein has a calculated molecular mass of 48,835 Da and a predicted pI of 4.6. An alignment of the AglB amino acid sequence with those of other α-galactosidases revealed that it belongs to a subfamily of α-galactosidases that also includesA. niger AglA. A. niger AglC belongs to a different subfamily that consists mainly of prokaryotic α-galactosidases. The expression of aglA,aglB, aglC, and lacA, the latter of which encodes an A. niger β-galactosidase, has been studied by using a number of monomeric, oligomeric, and polymeric compounds as growth substrates. Expression of aglA is only detected on galactose and galactose-containing oligomers and polymers. The aglB gene is expressed on all of the carbon sources tested, including glucose. Elevated expression was observed on xylan, which could be assigned to regulation via XlnR, the xylanolytic transcriptional activator. Expression of aglC was only observed on glucose, fructose, and combinations of glucose with xylose and galactose. High expression of lacA was detected on arabinose, xylose, xylan, and pectin. Similar to aglB, the expression on xylose and xylan can be assigned to regulation via XlnR. All four genes have distinct expression patterns which seem to mirror the natural substrates of the encoded proteins.

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Coker, James A., Peter P. Sheridan, Jennifer Loveland-Curtze, Kevin R. Gutshall, Ann J. Auman, and Jean E. Brenchley. "Biochemical Characterization of a β-Galactosidase with a Low Temperature Optimum Obtained from an Antarctic Arthrobacter Isolate." Journal of Bacteriology 185, no. 18 (September 15, 2003): 5473–82. http://dx.doi.org/10.1128/jb.185.18.5473-5482.2003.

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ABSTRACT A psychrophilic gram-positive isolate was obtained from Antarctic Dry Valley soil. It utilized lactose, had a rod-coccus cycle, and contained lysine as the diamino acid in its cell wall. Consistent with these physiological traits, the 16S ribosomal DNA sequence showed that it was phylogenetically related to other Arthrobacter species. A gene (bgaS) encoding a family 2 β-galactosidase was cloned from this organism into an Escherichia coli host. Preliminary results showed that the enzyme was cold active (optimal activity at 18°C and 50% activity remaining at 0°C) and heat labile (inactivated within 10 min at 37°C). To enable rapid purification, vectors were constructed adding histidine residues to the BgaS enzyme and its E. coli LacZ counterpart, which was purified for comparison. The His tag additions reduced the specific activities of both β-galactosidases but did not alter the other characteristics of the enzymes. Kinetic studies using o-nitrophenyl-β-d-galactopyranoside showed that BgaS with and without a His tag had greater catalytic activity at and below 20°C than the comparable LacZ β-galactosidases. The BgaS heat lability was investigated by ultracentrifugation, where the active enzyme was a homotetramer at 4°C but dissociated into inactive monomers at 25°C. Comparisons of family 2 β-galactosidase amino acid compositions and modeling studies with the LacZ structure did not mimic suggested trends for conferring enzyme flexibility at low temperatures, consistent with the changes affecting thermal adaptation being localized and subtle. Mutation studies of the BgaS enzyme should aid our understanding of such specific, localized changes affecting enzyme thermal properties.

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Sánchez-Aparicio, M. Teresa, María Flora Rosas, Rosa Maria Ferraz, Laura Delgui, Juan J. Veloso, Esther Blanco, Antonio Villaverde, and Francisco Sobrino. "Discriminating Foot-and-Mouth Disease Virus-Infected and Vaccinated Animals by Use of β-Galactosidase Allosteric Biosensors." Clinical and Vaccine Immunology 16, no. 8 (June 24, 2009): 1228–35. http://dx.doi.org/10.1128/cvi.00139-09.

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ABSTRACT Recombinant β-galactosidases accommodating one or two different peptides from the foot-and-mouth disease virus (FMDV) nonstructural protein 3B per enzyme monomer showed a drastic enzymatic activity reduction, which mainly affected proteins with double insertions. Recombinant β-galactosidases were enzymatically reactivated by 3B-specific murine monoclonal and rabbit polyclonal antibodies. Interestingly, these recombinant β-galactosidases, particularly those including one copy of each of the two 3B sequences, were efficiently reactivated by sera from infected pigs. We found reaction conditions that allowed differentiation between sera of FMDV-infected pigs, cattle, and sheep and those of naïve and conventionally vaccinated animals. These FMDV infection-specific biosensors can provide an effective and versatile alternative for the serological distinction of FMDV-infected animals.

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Fessner, Wolf-Dieter, and Juan Manuel Juárez Ruiz. "Regiospecific synthesis of lactose analog Gal-(β 1,4)-Xyl by transgalactosylation." Canadian Journal of Chemistry 80, no. 6 (June 1, 2002): 739–42. http://dx.doi.org/10.1139/v02-106.

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A short enzymatic synthesis of disaccharide 4-O-β-D-galactopyranosyl-D-xylose (1) has been developed, which is of interest as a lactose analog for a non-invasive medicinal determination of lactose intolerance. The starting material, benzyl α-D-xyloside, was obtained by a Fischer-type glycosidation of D-xylose with benzyl alcohol, followed by anomeric differentiation of mixed glycosides using a glycosidase from Aspergillus oryzae. From several commercial β-galactosidases, which were screened for their transgalactosylation capacity, the enzyme from Escherichia coli was found to catalyze a virtually regio- and stereospecific galactosyl transfer from donor compounds o-nitrophenyl β-D-galactoside or lactose to the α-D-xyloside. Subsequent hydrogenolytic deprotection furnished desired disaccharide 1.Key words: oligosaccharide synthesis, β-galactosidase, lactose intolerance.

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Volford, Bettina, Mónika Varga, András Szekeres, Alexandra Kotogán, Gábor Nagy, Csaba Vágvölgyi, Tamás Papp, and Miklós Takó. "β-Galactosidase-Producing Isolates in Mucoromycota: Screening, Enzyme Production, and Applications for Functional Oligosaccharide Synthesis." Journal of Fungi 7, no. 3 (March 19, 2021): 229. http://dx.doi.org/10.3390/jof7030229.

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β-Galactosidases of Mucoromycota are rarely studied, although this group of filamentous fungi is an excellent source of many industrial enzymes. In this study, 99 isolates from the genera Lichtheimia, Mortierella, Mucor, Rhizomucor, Rhizopus and Umbelopsis, were screened for their β-galactosidase activity using a chromogenic agar approach. Ten isolates from the best producers were selected, and the activity was further investigated in submerged (SmF) and solid-state (SSF) fermentation systems containing lactose and/or wheat bran substrates as enzyme production inducers. Wheat bran proved to be efficient for the enzyme production under both SmF and SSF conditions, giving maximum specific activity yields from 32 to 12,064 U/mg protein and from 783 to 22,720 U/mg protein, respectively. Oligosaccharide synthesis tests revealed the suitability of crude β-galactosidases from Lichtheimia ramosa Szeged Microbiological Collection (SZMC) 11360 and Rhizomucor pusillus SZMC 11025 to catalyze transgalactosylation reactions. In addition, the crude enzyme extracts had transfructosylation activity, resulting in the formation of fructo-oligosaccharide molecules in a sucrose-containing environment. The maximal oligosaccharide concentration varied between 0.0158 and 2.236 g/L depending on the crude enzyme and the initial material. Some oligosaccharide-enriched mixtures supported the growth of probiotics, indicating the potential of the studied enzyme extracts in future prebiotic synthesis processes.

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Gavalda, Elisabeth, Pascal Degraeve, and Pierre Lemay. "High-pressure-induced modulation of the antigenic interactions between two β-galactosidases and anti-β-galactosidase antibodies." Enzyme and Microbial Technology 18, no. 1 (January 1996): 10–17. http://dx.doi.org/10.1016/0141-0229(96)00043-9.

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Kurogochi, Masaki, Shin-Ichiro Nishimura, and Yuan Chuan Lee. "Mechanism-based Fluorescent Labeling of β-Galactosidases." Journal of Biological Chemistry 279, no. 43 (August 12, 2004): 44704–12. http://dx.doi.org/10.1074/jbc.m401718200.

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Perrin, D. "IMMUNOLOGICAL STUDIES WITH GENETICALLY ALTERED β-GALACTOSIDASES*." Annals of the New York Academy of Sciences 103, no. 2 (December 15, 2006): 1058–66. http://dx.doi.org/10.1111/j.1749-6632.1963.tb53757.x.

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Tanaka, Takeshi, Toshiaki Fukui, Haruyuki Atomi, and Tadayuki Imanaka. "Characterization of an Exo-β-d-Glucosaminidase Involved in a Novel Chitinolytic Pathway from the Hyperthermophilic Archaeon Thermococcus kodakaraensis KOD1." Journal of Bacteriology 185, no. 17 (September 1, 2003): 5175–81. http://dx.doi.org/10.1128/jb.185.17.5175-5181.2003.

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ABSTRACT We previously clarified that the chitinase from the hyperthermophilic archaeon Thermococcus kodakaraensis KOD1 produces diacetylchitobiose (GlcNAc2) as an end product from chitin. Here we sought to identify enzymes in T. kodakaraensis that were involved in the further degradation of GlcNAc2. Through a search of the T. kodakaraensis genome, one candidate gene identified as a putative β-glycosyl hydrolase was found in the near vicinity of the chitinase gene. The primary structure of the candidate protein was homologous to the β-galactosidases in family 35 of glycosyl hydrolases at the N-terminal region, whereas the central region was homologous to β-galactosidases in family 42. The purified protein from recombinant Escherichia coli clearly showed an exo-β-d-glucosaminidase (GlcNase) activity but not β-galactosidase activity. This GlcNase (GlmA Tk ), a homodimer of 90-kDa subunits, exhibited highest activity toward reduced chitobiose at pH 6.0 and 80°C and specifically cleaved the nonreducing terminal glycosidic bond of chitooligosaccharides. The GlcNase activity was also detected in T. kodakaraensis cells, and the expression of GlmA Tk was induced by GlcNAc2 and chitin, strongly suggesting that GlmA Tk is involved in chitin catabolism in T. kodakaraensis. These results suggest that T. kodakaraensis, unlike other organisms, possesses a novel chitinolytic pathway where GlcNAc2 from chitin is first deacetylated and successively hydrolyzed to glucosamine. This is the first report that reveals the primary structure of GlcNase not only from an archaeon but also from any organism.

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Otieno, Daniel Obed. "Synthesis of β-Galactooligosaccharides from Lactose Using Microbial β-Galactosidases." Comprehensive Reviews in Food Science and Food Safety 9, no. 5 (August 26, 2010): 471–82. http://dx.doi.org/10.1111/j.1541-4337.2010.00121.x.

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Vera, Carlos, Cecilia Guerrero, Lorena Wilson, and Andrés Illanes. "Synthesis of butyl-β- d -galactoside with commercial β-galactosidases." Food and Bioproducts Processing 103 (May 2017): 66–75. http://dx.doi.org/10.1016/j.fbp.2017.02.007.

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Wang, Yan, and Gisèle LaPointe. "Arabinogalactan Utilization by Bifidobacterium longum subsp. longum NCC 2705 and Bacteroides caccae ATCC 43185 in Monoculture and Coculture." Microorganisms 8, no. 11 (October 31, 2020): 1703. http://dx.doi.org/10.3390/microorganisms8111703.

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Arabinogalactan (AG) has been studied as a potential prebiotic in view of stimulating bifidobacteria presence in the gut microbiota. However, bifidobacteria prefer fermentation of oligosaccharides to that of polysaccharides. The contribution of other gut bacteria may allow better growth of bifidobacteria on AG. β-galactanases and β-galactosidases are the main enzymes for the degradation of AG. Additional enzymes such as α-L-arabinofuranosidase and β-L-arabinopyranosidase are required to remove the arabinose side chains. All of these predicted functions are encoded by the genomes of both Bifidobacterium longum subsp. longum NCC 2705 and Bacteroides caccae ATCC 43185. However, neither strain was able to grow significantly on AG, with 25% (B. longum subsp. longum NCC 2705) and 39% (Bac. caccae ATCC 43185) of AG degraded after 48-h fermentation, respectively. In this study, the β-galactanase, β-galactosidase, α-L-arabinofuranosidase, and β-L-arabinopyranosidase from both strains were investigated. The extracellular β-galactosidases of both B. longum subsp. longum NCC 2705 and Bac. caccae ATCC 43185 were able to cleave the β-1,3; 1,4 and 1,6 linkages. However, the β-galactosidase activity of B. longum subsp. longum NCC 2705 was weaker for the β-1,4 linkage, compared with the β-1,3 and 1,6 linkages. The arabinose side chains of AG inhibited the cleavage of β-1,3 and 1,6 linkages by the endo-β-galactanase from both strains, and partially inhibited the cleavage of β-1,4 linkages by the endo-β-1,4 galactanase from Bac. caccae ATCC 43185. The α-L-arabinofuranosidase and β-L-arabinopyranosidase from both strains were unable to cleave arabinose from AG under the conditions used. These results show limited breakdown of AG by these two strains in monoculture. When cocultured with Bac. caccae ATCC 43185, B. longum subsp. longum NCC 2705 grew significantly better than in monoculture on AG after 6 h of fermentation (p < 0.05). The coculture showed 48% AG degradation after 48 h of fermentation, along with reduced pH. Furthermore, compared to monoculture of Bac. caccae ATCC 43185, the concentration of succinate significantly increased from 0.01 ± 0.01 to 4.41 ± 0.61 mM, whereas propionate significantly decreased from 13.07 ± 0.37 to 9.75 ± 2.01 mM in the coculture (p < 0.05). These results suggest that the growth and metabolic activities of Bac. caccae ATCC 43185 were restrained in the coculture, as the pH decreased due to the metabolism of B. longum subsp. longum NCC 2705.

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Ring, Mark, and Reuben E. Huber. "The properties of β-galactosidases (Escherichia coli) with halogenated tyrosines." Biochemistry and Cell Biology 71, no. 3-4 (March 1, 1993): 127–32. http://dx.doi.org/10.1139/o93-021.

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An Escherichia coli tyrosine auxotroph (MR1) with an inducible lacZ was generated by mutagenesis. Of several tyrosine derivatives tested, only m-fluorotyrosine supported the growth of this mutant and allowed synthesis of active β-galactosidase. The pH profiles of the β-galactosidase that was obtained when this mutant was grown on m-fluorotyrosine (81.5% of the tyrosine was replaced by m-fluorotyrosine) indicated that a tyrosine may be acting as a general acid–base catalyst and that it (or another tyrosine with the same pKa) may be involved in substrate binding. Inactivation of normal β-galactosidase by treatment with lactoperoxidase in the presence of I− did not affect affinity-column binding, but incubation of this iodinated β-galactosidase with chymotrypsin caused a rapid degradation of a portion of the treated enzyme equal to the portion of the activity that was lost. A study with 125I− showed that the rapid degradation was mainly confined to iodinated molecules of enzyme. These studies indicate that iodination of β-galactosidase does not affect binding ability, but causes the enzyme to lose catalytic activity and become susceptible to chymotryptic action. Chloroperoxidase also caused rapid inactivation of normal β-galactosidase in the presence of Br− or I−, but there was a lag followed by a slow inactivation in the presence of CI−.Key words: β-galactosidase, tyrosine, halogenation, lactoperoxidase, mechanism.

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Li, Zhu, and Xing. "A New β-Galactosidase from the Antarctic Bacterium Alteromonas sp. ANT48 and Its Potential in Formation of Prebiotic Galacto-Oligosaccharides." Marine Drugs 17, no. 11 (October 23, 2019): 599. http://dx.doi.org/10.3390/md17110599.

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As an important medical enzyme, β-galactosidases catalyze transgalactosylation to form prebiotic Galacto-Oligosaccharides (GOS) that assist in improving the effect of intestinal flora on human health. In this study, a new glycoside hydrolase family 2 (GH2) β-galactosidase-encoding gene, galA, was cloned from the Antarctic bacterium Alteromonas sp. ANT48 and expressed in Escherichia coli. The recombinant β-galactosidase GalA was optimal at pH 7.0 and stable at pH 6.6–7.0, which are conditions suitable for the dairy environment. Meanwhile, GalA showed most activity at 50 °C and retained more than 80% of its initial activity below 40 °C, which makes this enzyme stable in normal conditions. Molecular docking with lactose suggested that GalA could efficiently recognize and catalyze lactose substrates. Furthermore, GalA efficiently catalyzed lactose degradation and transgalactosylation of GOS in milk. A total of 90.6% of the lactose in milk could be hydrolyzed within 15 min at 40 °C, and the GOS yield reached 30.9%. These properties make GalA a good candidate for further applications.

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Husain, Qayyum. "β Galactosidases and their potential applications: a review." Critical Reviews in Biotechnology 30, no. 1 (February 9, 2010): 41–62. http://dx.doi.org/10.3109/07388550903330497.

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Petrini, M., P. Trentini, M. Ferrante, L. D'Alessandro, and G. Spoto. "Spectrophotometric assessment of salivary β-galactosidases in halitosis." Journal of Breath Research 6, no. 2 (March 19, 2012): 021001. http://dx.doi.org/10.1088/1752-7155/6/2/021001.

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Pilipenko, O. S., L. F. Atyaksheva, and E. S. Chukhrai. "Inhibition of β-galactosidases with mono- and disaccharides." Russian Journal of Physical Chemistry A 84, no. 1 (December 29, 2009): 118–22. http://dx.doi.org/10.1134/s003602441001022x.

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Vera, Carlos, Cecilia Guerrero, Carla Aburto, Andrés Cordova, and Andrés Illanes. "Conventional and non-conventional applications of β-galactosidases." Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 1868, no. 1 (January 2020): 140271. http://dx.doi.org/10.1016/j.bbapap.2019.140271.

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Niu, Dandan, Xiaojing Tian, Nokuthula Peace Mchunu, Chao Jia, Suren Singh, Xiaoguang Liu, Bernard A. Prior, and Fuping Lu. "Biochemical characterization of three Aspergillus niger β-galactosidases." Electronic Journal of Biotechnology 27 (May 2017): 37–43. http://dx.doi.org/10.1016/j.ejbt.2017.03.001.

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Sudério, Fabrício Bonfim, Gislainy Karla da Costa Barbosa, Enéas Gomes-Filho, and Joaquim Enéas-Filho. "O estresse salino retarda o desenvolvimento morfofisiológico e a ativação de galactosidases de parede celular em caules de Vigna unguiculata." Acta Botanica Brasilica 25, no. 1 (March 2011): 17–24. http://dx.doi.org/10.1590/s0102-33062011000100004.

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Com o objetivo de examinar o envolvimento das α- e β-galactosidases na expansão celular de caules de plântulas de feijão-de-corda submetidas a estresse salino durante o estabelecimento da plântula, e de analisar os efeitos do estresse salino no desenvolvimento das plântulas e nas atividades enzimáticas, sementes de feijão-de-corda Pitiúba foram semeadas em água destilada e em solução de NaCl 100 mM. Foram coletados caules em diferentes estádios de desenvolvimento e com diferentes tempos após a semeadura. Avaliou-se o crescimento através das medidas de comprimento e das matérias fresca e seca dos caules. A salinidade tanto inibiu como retardou o crescimento dos caules. Os efeitos do NaCl nas atividades galactosidásicas de parede celular foram estudados in vivo e in vitro. A inibição e o retardamento do crescimento dos caules correlacionaram-se com as variações em atividades galactosidásicas. As galactosidases de parede celular de caules de plântulas tiveram suas atividades inibidas com o aumento da concentração de sal no meio de reação. A partir de 250 mM de NaCl as β-galactosidases foram mais sensíveis ao sal que α-galactosidases.

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Taron, Christopher H., Jack S. Benner, Linda J. Hornstra, and Ellen P. Guthrie. "A novel β-galactosidase gene isolated from the bacterium Xanthomonas manihotis exhibits strong homology to several eukaryotic β-galactosidases." Glycobiology 5, no. 6 (1995): 603–10. http://dx.doi.org/10.1093/glycob/5.6.603.

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Samoshin, Andrey V., Irina A. Dotsenko, Nataliya M. Samoshina, Andreas H. Franz, and Vyacheslav V. Samoshin. "Thio-β-D-glucosides: Synthesis and Evaluation as Glycosidase Inhibitors and Activators." International Journal of Carbohydrate Chemistry 2014 (August 21, 2014): 1–8. http://dx.doi.org/10.1155/2014/941059.

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Structurally simple 1-thio-β-D-glucopyranosides were synthesized and tested as potential inhibitors toward several fungal glycosidases from Aspergillus oryzae and Penicillium canescens. Significant selective inhibition was observed for α- and β-glucosidases, while a weak to moderate activation for α- and β-galactosidases.

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Rempel, B. P., and S. G. Withers. "Phosphodiesters serve as potentially tunable aglycones for fluoro sugar inactivators of retaining β-glycosidases." Org. Biomol. Chem. 12, no. 16 (2014): 2592–95. http://dx.doi.org/10.1039/c4ob00235k.

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2-Deoxy-2-fluoroglycosides were synthesised and tested as covalent glycosidase inactivators. β-d-Gluco-, -manno- and -galacto-configured benzyl-benzylphosphonate derivatives efficiently inactivate β-gluco-, β-manno- and β-galactosidases, while α-gluco- and α-manno-configured phosphate and phosphonate derivatives instead served as slow substrates for their cognate α-glycosidases.

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Coombs, Jonna M., and Jean E. Brenchley. "Biochemical and Phylogenetic Analyses of a Cold-Active β-Galactosidase from the Lactic Acid Bacterium Carnobacterium piscicola BA." Applied and Environmental Microbiology 65, no. 12 (December 1, 1999): 5443–50. http://dx.doi.org/10.1128/aem.65.12.5443-5450.1999.

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ABSTRACT We are investigating glycosyl hydrolases from new psychrophilic isolates to examine the adaptations of enzymes to low temperatures. A β-galactosidase from isolate BA, which we have classified as a strain of the lactic acid bacterium Carnobacterium piscicola, was capable of hydrolyzing the chromogen 5-bromo-4-chloro-3-indolyl β-d-galactopyranoside (X-Gal) at 4°C and possessed higher activity in crude cell lysates at 25 than at 37°C. Sequence analysis of a cloned DNA fragment encoding this activity revealed a gene cluster containing three glycosyl hydrolases with homology to an α-galactosidase and two β-galactosidases. The larger of the two β-galactosidase genes, bgaB, encoded the 76.8-kDa cold-active enzyme. This gene was homologous to family 42 glycosyl hydrolases, a group which contains several thermophilic enzymes but none from lactic acid bacteria. The bgaB gene from isolate BA was subcloned in Escherichia coli, and its enzyme, BgaB, was purified. The purified enzyme was highly unstable and required 10% glycerol to maintain activity. Its optimal temperature for activity was 30°C, and it was inactivated at 40°C in 10 min. TheKm of freshly purified enzyme at 30°C was 1.7 mM, and the V max was 450 μmol · min−1 · mg−1 with o-nitrophenyl β-d-galactopyranoside. This cold-active enzyme is interesting because it is homologous to a thermophilic enzyme fromBacillus stearothermophilus, and comparisons could provide information about structural features important for activity at low temperatures.

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Journal articles on the topic 'Β-galactosidases'

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