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Journal articles on the topic 'Tyrosine oxidation'

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Published: 10 December 2022

Last updated: 28 January 2023

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1

Naish-Byfield, S., and P. A. Riley. "Oxidation of monohydric phenol substrates by tyrosinase. An oximetric study." Biochemical Journal 288, no. 1 (November 15, 1992): 63–67. http://dx.doi.org/10.1042/bj2880063.

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The purity of commercially available mushroom tyrosinase was investigated by non-denaturing PAGE. Most of the protein in the preparation migrated as a single band under these conditions. This band contained both tyrosinase and dopa oxidase activity. No other activity of either classification was found in the preparation. Oxygen consumption by tyrosinase during oxidation of the monohydric phenol substrates tyrosine and 4-hydroxyanisole (4HA) was monitored by oximetry in order to determine the stoichiometry of the reactions. For complete oxidation, the molar ratio of oxygen: 4HA was 1:1. Under identical conditions, oxidation of tyrosine required 1.5 mol of oxygen/mol of tyrosine. The additional oxygen uptake during tyrosine oxidation is due to the internal cyclization of dopaquinone to form cyclodopa, which undergoes a redox reaction with dopaquinone to form dopachrome and dopa, which is then oxidized by the enzyme, leading to an additional 0.5 mol of oxygen/mol of original substrate. Oxygen consumption for complete oxidation of 200 nmol of 4HA was constant over a range of concentrations of tyrosinase of 33-330 units/ml of substrate. The maximum rate of reaction was directly proportional to the concentration of tyrosinase, whereas the length of the lag phase decreased non-linearly with increasing tyrosinase concentration. Activation of the enzyme by exposure to citrate was not seen, nor was the lag phase abolished by exposure of the enzyme to low pH. Michaelis-Menten analysis of tyrosinase in which the lag phase is abolished by pre-exposure of the enzyme to a low concentration of dithiothreitol gave Km values for tyrosine and 4HA of 153 and 20 microM respectively.

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2

Sun, Biyun, A. Daryl Ariawan, Holly Warren, Sophia C. Goodchild, Marc in het Panhuis, Lars M. Ittner, and Adam D. Martin. "Programmable enzymatic oxidation of tyrosine–lysine tetrapeptides." Journal of Materials Chemistry B 8, no. 15 (2020): 3104–12. http://dx.doi.org/10.1039/d0tb00250j.

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Fmoc-capped tetrapeptides bearing two lysines and two tyrosines show programmable enzymatic activity. Solvent accessible tyrosines determine the extent of reactivity with tyrosinase, and subsequent quinone formation drives polymerisation.

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3

Nirmala, N. Baby, and P. Vani P. Vani. "Oxidation of L-Tyrosine by Tetrachloroaurate(III) – a Kinetic Study." International Journal of Scientific Research 2, no. 4 (June 1, 2012): 25–27. http://dx.doi.org/10.15373/22778179/apr2013/11.

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4

Moller, Matias N., Duane M. Hatch, Hye-Young H. Kim, and Ned a. Porter. "Tyrosine Oxidation-Derived Electrophiles." Free Radical Biology and Medicine 51 (November 2011): S148. http://dx.doi.org/10.1016/j.freeradbiomed.2011.10.254.

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5

Mariano, Alessia, Irene Bigioni, Anna Scotto d’Abusco, Alessia Baseggio Conrado, Simonetta Maina, Antonio Francioso, Luciana Mosca, and Mario Fontana. "Pheomelanin Effect on UVB Radiation-Induced Oxidation/Nitration of l-Tyrosine." International Journal of Molecular Sciences 23, no. 1 (December 27, 2021): 267. http://dx.doi.org/10.3390/ijms23010267.

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Pheomelanin is a natural yellow-reddish sulfur-containing pigment derived from tyrosinase-catalyzed oxidation of tyrosine in presence of cysteine. Generally, the formation of melanin pigments is a protective response against the damaging effects of UV radiation in skin. However, pheomelanin, like other photosensitizing substances, can trigger, following exposure to UV radiation, photochemical reactions capable of modifying and damaging cellular components. The photoproperties of this natural pigment have been studied by analyzing pheomelanin effect on oxidation/nitration of tyrosine induced by UVB radiation at different pH values and in presence of iron ions. Photoproperties of pheomelanin can be modulated by various experimental conditions, ranging from the photoprotection to the triggering of potentially damaging photochemical reactions. The study of the photomodification of l-Tyrosine in the presence of the natural pigment pheomelanin has a special relevance, since this tyrosine oxidation/nitration pathway can potentially occur in vivo in tissues exposed to sunlight and play a role in the mechanisms of tissue damage induced by UV radiation.

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6

Tien, Ming. "Myeloperoxidase-Catalyzed Oxidation of Tyrosine." Archives of Biochemistry and Biophysics 367, no. 1 (July 1999): 61–66. http://dx.doi.org/10.1006/abbi.1999.1226.

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7

KRAPFENBAUER, K., R. BIRNBACHER, H. VIERHAPPER, K. HERKNER, D. KAMPEL, and G. LUBEC. "Glycoxidation, and protein and DNA oxidation in patients with diabetes mellitus." Clinical Science 95, no. 3 (September 1, 1998): 331–37. http://dx.doi.org/10.1042/cs0950331.

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1.The role of oxidative stress in the pathogenesis of the diabetic state is being investigated extensively. Although oxidative stress has been reported in terms of glycoxidation, protein oxidation and DNA oxidation in diabetes mellitus, oxidation parameters have not been determined in parallel on the same study population. 2.We studied 24 patients with diabetes mellitus (14 patients with Type I diabetes with a mean age of 62.3±6.3 years and 10 patients with Type II diabetes aged 67.3±5.9 years) and compared them with age-matched non-diabetic controls. Urinary o-tyrosine, 8-hydroxy-2′-deoxyguanosine and pentosidine measurements by HPLC were made on two occasions (t1 and t2). 3.A clear statistical difference was found between diabetic patients and controls at t1 or t2 for 8-hydroxy-2′-deoxyguanosine and pentosidine, but not for o-tyrosine. No significant correlations were found between clinical and other laboratory parameters except high-density lipoprotein and uric acid. We revealed significantly increased glycoxidation and DNA oxidation in patients with Type I and Type II diabetes, but protein oxidation was not different from controls. 4.The finding of increased glycoxidation reflects increased oxidation of the carbohydrate moiety, whereas the increased levels of oxidized DNA may also be interpreted as due to increased DNA repair. The increased 8-hydroxy-2′-deoxyguanosine does not indicate the generation of an individual active oxygen species, but DNA could have been oxidized simply by alkenals from lipid peroxidation, as e.g. malondialdehyde. As no difference in protein oxidation (i.e. o-tyrosine) between diabetics and controls could be revealed, the oxidation of DNA by hydroxyl radical attack is unlikely, as o-tyrosine was proposed as a marker for hydroxyl radical attack. Therefore, the message is that increased glycoxidation can be confirmed, protein oxidation does not appear to take place and increased DNA oxidation is still not proven, as increased 8-hydroxy-2′-deoxyguanosine may simply reflect repair.

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8

Saleh, Maysoon B., and Russell G. Kerr. "Oxidation of Tyrosine Diketopiperazine to DOPA Diketopiperazine with Tyrosine Hydroxylase†." Journal of Natural Products 67, no. 8 (August 2004): 1390–91. http://dx.doi.org/10.1021/np034083j.

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9

Palumbo, A., G. Misuraca, M. D'Ischia, and G. Prota. "Effect of metal ions on the kinetics of tyrosine oxidation catalysed by tyrosinase." Biochemical Journal 228, no. 3 (June 15, 1985): 647–51. http://dx.doi.org/10.1042/bj2280647.

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The conversion of tyrosine into dopa [3-(3,4-dihydroxyphenyl)alanine] is the rate limiting step in the biosynthesis of melanins catalysed by tyrosinase. This hydroxylation reaction is characterized by a lag period, the extent of which depends on various parameters, notably the presence of a suitable hydrogen donor such as dopa or tetrahydropterin. We have now found that catalytic amounts of Fe2+ ions have the same effect as dopa in stimulating the tyrosine hydroxylase activity of the enzyme. Kinetic experiments showed that the shortening of the induction time depends on the concentration of the added metal and the nature of the buffer system used and is not suppressed by superoxide dismutase, catalase, formate or mannitol. Notably, Fe3+ ions showed only a small delaying effect on tyrosinase activity. Among the other metals which were tested, Zn2+, Co2+, Cd2+ and Ni2+ had no detectable influence, whereas Cu2+ and Mn2+ exhibited a marked inhibitory effect on the kinetics of tyrosine oxidation. These findings are discussed in the light of the commonly accepted mechanism of action of tyrosinase.

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10

Adamiec, J., K. Cejpek, J. Rössner, and J. Velíšek. "Novel Strecker degradation products of tyrosine and dihydroxyphenylalanine." Czech Journal of Food Sciences 19, No. 1 (February 7, 2013): 13–18. http://dx.doi.org/10.17221/6568-cjfs.

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Tyrosine was oxidised with either potassium peroxodisulphate or glyoxal. Volatile reaction products were isolated and analysed by GC/FID and GC/MS, derivatised with diazomethane and analysed by the same methods. Eight reaction products were identified. The major products were the expected Strecker aldehyde (4-hydroxyphenylacetaldehyde) and its lower homologue 4-hydroxybenzaldehyde. They were followed by 1-(4-hydroxyphenyl)-3-propionaldehyde, phenylacetaldehyde, benzaldehyde, phenol, 4-hydroxybenzoic, and benzoic acid. Analogously, the oxidation of 3,4-dihydroxyphenylalanine yielded the corresponding Strecker aldehyde (3,4-dihydroxyphenylacetaldehyde), its lower homologue 3,4-dihydroxybenzaldehyde, 3,4-dihydroxybenzoic, 3,4-dihydroxyphenylacetic, and caffeic acid. An identification of these oxidation products of tyrosine and 3,4-dihydroxyphenylalanine assumes homolytic cleavage of the Strecker aldehydes and a recombination of free radicals formed by this cleavage. As minor products, six O- and N-heterocyclic compounds arose in systems containing glyoxal (pyrazine, methyl- and ethylpyrazine, 3-furancarbaldehyde, 5-methyl-2-furancarbaldehyde, 2-pyrrolcarbaldehyde).

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11

MORIN, Bénédicte, J. Michael DAVIES, and T. Roger DEAN. "The protein oxidation product 3,4-dihydroxyphenylalanine (DOPA) mediates oxidative DNA damage." Biochemical Journal 330, no. 3 (March 15, 1998): 1059–67. http://dx.doi.org/10.1042/bj3301059.

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A major product of hydroxy-radical addition to tyrosine is 3,4-dihydroxyphenylalanine (DOPA) which has reducing properties. Protein-bound DOPA (PB-DOPA) has been shown to be a major component of the stable reducing species formed during protein oxidation under several conditions. The aim of the present work was to investigate whether DOPA, and especially PB-DOPA, can mediate oxidative damage to DNA. We chose to generate PB-DOPA using mushroom tyrosinase, which catalyses the hydroxylation of tyrosine residues in protein. This permitted us to study the reactions of PB-DOPA in the virtual absence of other protein-bound oxidation products. The formation of two oxidation products of DNA, 8-oxo-7,8-dihydro-2ʹ-deoxyguanosine (8oxodG) and 5-hydroxy-2ʹ-deoxycytidine (5OHdC), were studied with a novel HPLC using gradient elution and an electrochemical detection method, which allowed the detection of both DNA modifications in a single experiment. We found that exposure of calf thymus DNA to DOPA or PB-DOPA resulted in the formation of 8oxodG and 5OHdC, with the former predominating. The formation of these DNA oxidation products by either DOPA or PB-DOPA depended on the presence of oxygen, and also on the presence and on the concentration of transition metal ions, with copper being more effective than iron. The yields of 8oxodG and 5OHdC increased with DOPA concentration in proteins. Thus PB-DOPA was able to promote further radical-generating events, which then transferred damage to other biomolecules such as DNA.

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12

Groen, Arnoud, Simone Lemeer, Thea van der Wijk, John Overvoorde, Albert J. R. Heck, Arne Ostman, David Barford, Monique Slijper, and Jeroen den Hertog. "Differential Oxidation of Protein-tyrosine Phosphatases." Journal of Biological Chemistry 280, no. 11 (December 28, 2004): 10298–304. http://dx.doi.org/10.1074/jbc.m412424200.

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13

GUNTHER, R. Michael, Richard A. TSCHIRRET-GUTH, H. Ewa WITKOWSKA, C. Yang FANN, P. David BARR, Paul R. ORTIZ DE MONTELLANO, and P. Ronald MASON. "Site-specific spin trapping of tyrosine radicals in the oxidation of metmyoglobin by hydrogen peroxide." Biochemical Journal 330, no. 3 (March 15, 1998): 1293–99. http://dx.doi.org/10.1042/bj3301293.

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The reaction between metmyoglobin and hydrogen peroxide produces both a ferryl-oxo heme and a globin-centred radical(s) from the two oxidizing equivalents of the hydrogen peroxide. Evidence has been presented for localization of the globin-centred radical on one tryptophan residue and tyrosines 103 and 151. When the spin-trapping agent 5,5-dimethyl-1-pyrroline N-oxide (DMPO) is included in the reaction mixture, a radical adduct has been detected, but the residue at which that adduct is formed has not been determined. Replacement of either tryptophans 7 and 14 or tyrosines 146 and 151 with phenylalanine has no effect on the formation of DMPO adduct in the reaction with hydrogen peroxide. When tyrosine 103 is replaced with phenylalanine, however, only DMPOX, a product of the oxidation of the spin-trap, is detected. Tyrosine-103 is, therefore, the site of radical adduct formation with DMPO. The spin trap 2-methyl-2-nitrosopropane (MNP), however, forms radical adducts with any recombinant sperm whale metmyoglobin that contains either tyrosine 103 or 151. Detailed spectral analysis of the DMPO and MNP radical adducts of isotopically substituted tyrosine radical yield complete structural determinations. The multiple sites of trapping support a model in which the unpaired electron density is spread over a number of residues in the population of metmyoglobin molecules, at least some of which are in equilibrium with each other.

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14

Leeuwenburgh, Christiaan, Polly A. Hansen, John O. Holloszy, and Jay W. Heinecke. "Oxidized amino acids in the urine of aging rats: potential markers for assessing oxidative stress in vivo." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 276, no. 1 (January 1, 1999): R128—R135. http://dx.doi.org/10.1152/ajpregu.1999.276.1.r128.

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Oxidative damage of proteins has been implicated in disease and aging. In vitro studies demonstrate that two unnatural amino acids, o,o′-dityrosine and o-tyrosine, are stable markers of protein oxidation. We have investigated the possibility that assaying these compounds in urine could provide a noninvasive way to determine levels of protein oxidation in vivo. Isotope dilution gas chromatography-mass spectrometry was used to quantify levels of o,o′-dityrosine and o-tyrosine in skeletal muscle and urine of aging rats subjected to two interventions: 1) dietary antioxidant supplementation and 2) exercise training. In both sedentary rats and exercise-trained rats, antioxidant therapy reduced levels of protein-bound o,o′-dityrosine in skeletal muscle. In contrast, antioxidant therapy or exercise training minimally affected o-tyrosine levels in this tissue. Levels of the oxidized amino acids in urine samples mirrored those of skeletal muscle proteins. Quantification of the levels of oxidized amino acids in urine may thus serve as a noninvasive measure of oxidative stress in vivo because they change in parallel with levels of protein-bound oxidized amino acids in skeletal muscle.

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15

Tyminski, Marcin, Katarzyna Ciacka, Pawel Staszek, Agnieszka Gniazdowska, and Urszula Krasuska. "Toxicity of meta-Tyrosine." Plants 10, no. 12 (December 17, 2021): 2800. http://dx.doi.org/10.3390/plants10122800.

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L-Tyrosine (Tyr) is one of the twenty proteinogenic amino acids and also acts as a precursor for secondary metabolites. Tyr is prone to modifications, especially under conditions of cellular redox imbalance. The oxidation of Tyr precursor phenylalanine leads to the formation of Tyr non-proteinogenic isomers, including meta-Tyr (m-Tyr), a marker of oxidative stress. The aim of this review is to summarize the current knowledge on m-Tyr toxicity. The direct m-Tyr mode of action is linked to its incorporation into proteins, resulting in their improper conformation. Furthermore, m-Tyr produced by some plants as an allelochemical impacts the growth and development of neighboring organisms. In plants, the direct harmful effect of m-Tyr is due to its modification of the proteins structure, whereas its indirect action is linked to the disruption of reactive oxygen and nitrogen species metabolism. In humans, the elevated concentration of m-Tyr is characteristic of various diseases and ageing. Indeed, m-Tyr is believed to play an important role in cancer physiology. Thus, since, in animal cells, m-Tyr is formed directly in response to oxidative stress, whereas, in plants, m-Tyr is also synthesized enzymatically and serves as a chemical weapon in plant–plant competition, the general concept of m-Tyr role in living organisms should be specified.

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16

Leeuwenburgh, Christiaan, Polly Hansen, Aviv Shaish, John O. Holloszy, and Jay W. Heinecke. "Markers of protein oxidation by hydroxyl radical and reactive nitrogen species in tissues of aging rats." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 274, no. 2 (February 1, 1998): R453—R461. http://dx.doi.org/10.1152/ajpregu.1998.274.2.r453.

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Many lines of evidence implicate oxidative damage in aging. Possible pathways include reactions that modify aromatic amino acid residues on proteins. o-Tyrosine is a stable marker for oxidation of protein-bound phenylalanine by hydroxyl radical, whereas 3-nitrotyrosine is a marker for oxidation of protein-bound tyrosine by reactive nitrogen species. To test the hypothesis that proteins damaged by hydroxyl radical and reactive nitrogen accumulate with aging, we used isotope dilution gas chromatography-mass spectrometry to measure levels of o-tyrosine and 3-nitrotyrosine in heart, skeletal muscle, and liver from young adult (9 mo) and old (24 mo) female Long-Evans/Wistar hybrid rats. We also measured these markers in young adult and old rats that received antioxidant supplements (α-tocopherol, β-carotene, butylated hydroxytoluene, and ascorbic acid) from the age of 5 mo. We found that aging did not significantly increase levels of protein-bound o-tyrosine or 3-nitrotyrosine in any of the tissues. Antioxidant supplementation had no effect on the levels of protein-bound o-tyrosine and 3-nitrotyrosine in either young or old animals. These observations indicate that the o-tyrosine and 3-nitrotyrosine do not increase significantly in heart, skeletal muscle, and liver in old rats, suggesting that proteins damaged by hydroxyl radical and reactive nitrogen species do not accumulate in these tissues with advancing age.

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17

Schreurs, V. V. A. M., H. A. Boekholt, R. E. Koopmanschap, and P. J. M. Weijs. "The metabolic utilization of amino acids: potentials of 14CO2 breath test measurements." British Journal of Nutrition 67, no. 2 (March 1992): 207–14. http://dx.doi.org/10.1079/bjn19920024.

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The present paper offers a dual 14CO2 breath test approach to study the metabolic utilization of free amino acids in the body. Using the carboxyl-[14C]isotopomer of an amino acid as the test substrate the percentage recovery of the isotope as 14CO2 reflects which part of the labelled amino acid flux has been decarboxylated. The residual C fragments may flow to total oxidation at least to the level recovered for the universal [14C]isotopomer. In the case that recovery for total oxidation is less than for decarboxylation, part of the [14C]fragments are retained in the body by either exchange or non-oxidative pathways. Utilization of tyrosine and leucine was measured in the post-absorptive phase in adult rats conditioned on isoenergetic diets containing 210, 75 or 0 g protein/kg. It was shown that the level of dietary protein exerts an influence on both decarboxylation and total oxidation. Although the responses of leucine and tyrosine were not different for total oxidation, there was a difference between the amino acids in their relative rate of decarboxylation. That this dual 14CO2 breath test approach can be used as a tool to evaluate whether the protein and amino acid supply has been adequate to support actual requirements is discussed.Amino acid utilization: Amino acid requirements: Leucine: Tyrosine

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18

Locy, Morgan L., Sunad Rangarajan, Sufen Yang, Mark R. Johnson, Karen Bernard, Ashish Kurundkar, Nathaniel B. Bone, et al. "Oxidative cross-linking of fibronectin confers protease resistance and inhibits cellular migration." Science Signaling 13, no. 644 (August 11, 2020): eaau2803. http://dx.doi.org/10.1126/scisignal.aau2803.

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The oxidation of tyrosine residues to generate o,o′-dityrosine cross-links in extracellular proteins is necessary for the proper function of the extracellular matrix (ECM) in various contexts in invertebrates. Tyrosine oxidation is also required for the biosynthesis of thyroid hormone in vertebrates, and there is evidence for oxidative cross-linking reactions occurring in extracellular proteins secreted by myofibroblasts. The ECM protein fibronectin circulates in the blood as a globular protein that dimerizes through disulfide bridges generated by cysteine oxidation. We found that cellular (fibrillar) fibronectin on the surface of transforming growth factor–β1 (TGF-β1)–activated human myofibroblasts underwent multimerization by o,o′-dityrosine cross-linking under reducing conditions that disrupt disulfide bridges, but soluble fibronectin did not. This reaction on tyrosine residues required both the TGF-β1–dependent production of hydrogen peroxide and the presence of myeloperoxidase (MPO) derived from inflammatory cells, which are active participants in wound healing and fibrogenic processes. Oxidative cross-linking of matrix fibronectin attenuated both epithelial and fibroblast migration and conferred resistance to proteolysis by multiple proteases. The abundance of circulating o,o′-dityrosine–modified fibronectin was increased in a murine model of lung fibrosis and in human subjects with interstitial lung disease compared to that in control healthy subjects. These studies indicate that tyrosine can undergo stable, covalent linkages in fibrillar fibronectin under inflammatory conditions and that this modification affects the migratory behavior of cells on such modified matrices, suggesting that this modification may play a role in both physiologic and pathophysiologic tissue repair.

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19

Kuhn, Donald M., Cheryl W. Aretha, and Timothy J. Geddes. "Peroxynitrite Inactivation of Tyrosine Hydroxylase: Mediation by Sulfhydryl Oxidation, not Tyrosine Nitration." Journal of Neuroscience 19, no. 23 (December 1, 1999): 10289–94. http://dx.doi.org/10.1523/jneurosci.19-23-10289.1999.

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20

Chiarugi, P., M. L. Taddei, and G. Ramponi. "Oxidation and tyrosine phosphorylation: synergistic or antagonistic cues in protein tyrosine phosphatases." CMLS Cellular and Molecular Life Sciences 62, no. 9 (May 2005): 931–36. http://dx.doi.org/10.1007/s00018-004-4448-1.

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21

Wen, X. "Electrocatalytic oxidation of ?-tyrosine by a nitroxide." Talanta 53, no. 5 (January 26, 2001): 1031–36. http://dx.doi.org/10.1016/s0039-9140(00)00597-x.

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22

Giulivi, C., N. J. Traaseth, and K. J. A. Davies. "Tyrosine oxidation products: analysis and biological relevance." Amino Acids 25, no. 3-4 (July 29, 2003): 227–32. http://dx.doi.org/10.1007/s00726-003-0013-0.

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23

Ito, Shosuke, and Ludger Kolbe. "Tyrosine peptides provide a color palette upon tyrosinase oxidation: nanosize does matter." Pigment Cell & Melanoma Research 30, no. 1 (November 30, 2016): 4–5. http://dx.doi.org/10.1111/pcmr.12540.

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24

Sjödin, Martin, Stenbjörn Styring, Björn Åkermark, Licheng Sun, and Leif Hammarström. "The mechanism for proton–coupled electron transfer from tyrosine in a model complex and comparisons with Y Z oxidation in photosystem II." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 357, no. 1426 (October 29, 2002): 1471–79. http://dx.doi.org/10.1098/rstb.2002.1142.

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In the water–oxidizing reactions of photosystem II (PSII), a tyrosine residue plays a key part as an intermediate electron–transfer reactant between the primary donor chlorophylls (the pigment P 680 ) and the water–oxidizing Mn cluster. The tyrosine is deprotonated upon oxidation, and the coupling between the proton reaction and electron transfer is of great mechanistic importance for the understanding of the water–oxidation mechanism. Within a programme on artificial photosynthesis, we have made and studied the proton–coupled tyrosine oxidation in a model system and been able to draw mechanistic conclusions that we use to interpret the analogous reactions in PSII.

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25

FU, Shanlin, Michael J. DAVIES, Roland STOCKER, and Roger T. DEAN. "Evidence for roles of radicals in protein oxidation in advanced human atherosclerotic plaque." Biochemical Journal 333, no. 3 (August 1, 1998): 519–25. http://dx.doi.org/10.1042/bj3330519.

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Oxidative damage might be important in atherogenesis. Oxidized lipids are present at significant concentrations in advanced human plaque, although tissue antioxidants are mostly present at normal concentrations. Indirect evidence of protein modification (notably derivatization of lysine) or oxidation has been obtained by immunochemical methods; the specificities of these antibodies are unclear. Here we present chemical determinations of six protein-bound oxidation products: dopa, o-tyrosine, m-tyrosine, dityrosine, hydroxyleucine and hydroxyvaline, some of which reflect particularly oxy-radical-mediated reaction pathways, which seem to involve mainly the participation of transition- metal ions. We compared the relative abundance of these oxidation products in normal intima, and in human carotid plaque samples with that observed after radiolytically generated hydroxyl radical attack on BSA in vitro. The close similarities in relative abundances in the latter two circumstances indicate that hydroxyl radical damage might occur in plaque. The relatively higher level of dityrosine in plaque than that observed after radiolysis suggests the additional involvement of HOCl-mediated reactions in advanced plaque.

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26

Gatin, Anouchka, Patricia Duchambon, Guillaume van der Rest, Isabelle Billault, and Cécile Sicard-Roselli. "Protein Dimerization via Tyr Residues: Highlight of a Slow Process with Co-Existence of Numerous Intermediates and Final Products." International Journal of Molecular Sciences 23, no. 3 (January 21, 2022): 1174. http://dx.doi.org/10.3390/ijms23031174.

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Protein dimerization via tyrosine residues is a crucial process in response to an oxidative attack, which has been identified in many ageing-related pathologies. Recently, it has been found that for isolated tyrosine amino acid, dimerization occurs through three types of tyrosine–tyrosine crosslinks and leads to at least four final products. Herein, considering two protected tyrosine residues, tyrosine-containing peptides and finally proteins, we investigate the dimerization behavior of tyrosine when embedded in a peptidic sequence. After azide radical oxidation and by combining UPLC-MS and H/D exchange analyzes, we were able to evidence: (i) the slow kinetics of Michael Addition Dimers (MAD) formation, i.e., more than 48 h; (ii) the co-existence of intermediates and final cyclized dimer products; and (iii) the probable involvement of amide functions to achieve Michael additions even in proteins. This raises the question of the possible in vivo existence of both intermediates and final entities as well as their toxicity and the potential consequences on protein structure and/or function.

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27

Lacombat, Fabien, Agathe Espagne, Nadia Dozova, Pascal Plaza, Elisabeth Ignatz, Stephan Kiontke, and Lars-Oliver Essen. "Delocalized hole transport coupled to sub-ns tryptophanyl deprotonation promotes photoreduction of class II photolyases." Physical Chemistry Chemical Physics 20, no. 39 (2018): 25446–57. http://dx.doi.org/10.1039/c8cp04548h.

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28

Alfassi, Zeev B. "Selective oxidation of tyrosine—Oxidation by NO2 and ClO2 at basic pH." International Journal of Radiation Applications and Instrumentation. Part C. Radiation Physics and Chemistry 29, no. 5 (January 1987): 405–6. http://dx.doi.org/10.1016/1359-0197(87)90014-2.

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29

Li, Yong Jin. "Optical Determination of L-tyrosine Based on Eggshell Membrane Immobilized Tyrosinase." Journal of AOAC INTERNATIONAL 93, no. 6 (November 1, 2010): 1912–15. http://dx.doi.org/10.1093/jaoac/93.6.1912.

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Abstract An optical biosensor based on the eggshell membrane immobilized tyrosinase is described for the detection of L-tyrosine (L-Tyr). The detection scheme was based on the measurement of absorption value of color adduct resulting from the reaction of 3-methyl-2-benzothiazolinone hydrazone and dopa-quinone produced from the enzymatic oxidation of L-Tyr. The prepared biosensor demonstrated optimum activity at pH 7, optimum temperature range of 2040C and a linear response for the L-Tyr concentration in range of 5200 M. It also showed good operation stability for repeated measurements (over 300 times) and storage stability after it had been kept at 4C for 3 months.

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30

Ruokolainen, Miina, Elisa Ollikainen, Tiina Sikanen, Tapio Kotiaho, and Risto Kostiainen. "Oxidation of Tyrosine-Phosphopeptides by Titanium Dioxide Photocatalysis." Journal of the American Chemical Society 138, no. 24 (June 14, 2016): 7452–55. http://dx.doi.org/10.1021/jacs.6b02472.

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Karisch, Robert, and Benjamin G. Neel. "Methods to monitor classical protein-tyrosine phosphatase oxidation." FEBS Journal 280, no. 2 (May 30, 2012): 459–75. http://dx.doi.org/10.1111/j.1742-4658.2012.08626.x.

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32

Saito, K., A. W. Rutherford, and H. Ishikita. "Mechanism of tyrosine D oxidation in Photosystem II." Proceedings of the National Academy of Sciences 110, no. 19 (April 18, 2013): 7690–95. http://dx.doi.org/10.1073/pnas.1300817110.

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Östman, Arne, Jeroen Frijhoff, Åsa Sandin, and Frank-D. Böhmer. "Regulation of protein tyrosine phosphatases by reversible oxidation." Journal of Biochemistry 150, no. 4 (August 19, 2011): 345–56. http://dx.doi.org/10.1093/jb/mvr104.

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Funato, Yosuke, and Hiroaki Miki. "Reversible oxidation of PRL family protein-tyrosine phosphatases." Methods 65, no. 2 (January 2014): 184–89. http://dx.doi.org/10.1016/j.ymeth.2013.06.032.

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35

Nugent, Jonathan H. A., Richard J. Ball, and Michael C. W. Evans. "Photosynthetic water oxidation: the role of tyrosine radicals." Biochimica et Biophysica Acta (BBA) - Bioenergetics 1655 (April 2004): 217–21. http://dx.doi.org/10.1016/j.bbabio.2003.09.015.

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36

Hunter, Luke, and Craig A. Hutton. "Preparation of Selectively Protected L-Dopa Derivatives: Oxidation of Tyrosine-3-boronates." Australian Journal of Chemistry 56, no. 11 (2003): 1095. http://dx.doi.org/10.1071/ch03181.

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Conversion of 3-iodo-L-tyrosine to protected tyrosine-3-boronate esters, followed by oxidation with hydrogen peroxide, provides a mild and efficient method for the preparation of selectively protected L-dopa derivatives.

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37

Maas, I. A. M., V. V. A. M. Schreurs, P. J. M. Weijs, M. Frings, B. A. C. van Acker, H. A. Boekholt, and R. E. Koopmanschap. "Combined effects of dietary restrictions and physical activity on amino acid utilization in rats." Netherlands Journal of Agricultural Science 37, no. 3 (September 1, 1989): 263–68. http://dx.doi.org/10.18174/njas.v37i3.16637.

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Female Wistar rats given protein- or energy-restricted diets or normal unrestricted diets for 1 or 7 weeks were subjected to intensive treadmill exercise. Injections of L-[U-14C]tyrosine, 21 h after the exercise, were used to trace amino acid oxidation and incorporation in tissue proteins of liver, kidneys, soleus muscle and muscles of the upper and lower foreleg. Protein restriction decreased tyrosine oxidation (expressed as percentage of the injected dose), with little effect on the incorporation in tissue proteins. Energy restriction increased tyrosine oxidation and decreased incorporation significantly. With energy restriction, amino acids are probably used to compensate for the lack of energy, resulting in a secondary protein restriction. Treadmill running, in combination with dietary protein and energy restriction, increased tyrosine incorporation in most of the tissues. The results indicate that, under dietary restriction (especially a low-energy normal-protein diet), a single bout of exercise can stimulate protein synthesis, even until 21 h after performance. On all diets the rise in tyrosine incorporation was highest for muscles of the foreleg. Recovery from muscle degeneration, resulting from exercise, might account for the increased protein synthesis. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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38

Zello, G. A., P. B. Pencharz, and R. O. Ball. "Phenylalanine flux, oxidation, and conversion to tyrosine in humans studied with L-[1-13C]phenylalanine." American Journal of Physiology-Endocrinology and Metabolism 259, no. 6 (December 1, 1990): E835—E843. http://dx.doi.org/10.1152/ajpendo.1990.259.6.e835.

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Phenylalanine metabolism was determined in 41 studies of adult males (n = 10) consuming an energy-sufficient diet and receiving graded levels of dietary phenylalanine and excess tyrosine (40 mg.kg-1.day-1). After a dietary adaptation period to either 4.2 or 14.0 mg.kg-1.day-1 of phenylalanine; flux, plasma concentration, oxidation, and conversion to tyrosine were measured at test phenylalanine intakes of 5, 7, 10, 14, 21, 28, or 60 mg.kg-1.day-1. Oxidation was low and constant (1.3 mumol.kg-1.h-1) at intakes at or below 10 mg.kg-1.day-1 and increased linearly above this level. Conversion to tyrosine was minimal (2.1%) at these intakes. Breakpoint analysis showed the phenylalanine requirement with excess tyrosine to be 9.1 mg.kg-1.day-1. Plasma phenylalanine concentrations confirmed this estimate of requirement. Prior adaptation did not significantly affect overall flux, plasma concentration, or oxidation nor did it affect the requirement estimate. With the assumption that tyrosine can supply two-thirds of the aromatic amino acid requirement, these data suggest that the aromatic amino acid requirement should be 30 mg.kg-1.day-1 and the World Health Organization recommendation of 14 mg.kg-1.day-1 is an underestimate.

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Jiang, Chao, Ya Li, Chenghui Liu, Liying Qiu, and Zhengping Li. "A general and versatile fluorescence turn-on assay for detecting the activity of protein tyrosine kinases based on phosphorylation-inhibited tyrosyl oxidation." Chemical Communications 52, no. 85 (2016): 12570–73. http://dx.doi.org/10.1039/c6cc07035c.

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Goodwin, P. H., and C. R. Sopher. "Brown pigmentation of Xanthomonas campestris pv. phaseoli associated with homogentisic acid." Canadian Journal of Microbiology 40, no. 1 (January 1, 1994): 28–34. http://dx.doi.org/10.1139/m94-005.

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The diffusible brown pigment produced by some strains of Xanthomonas campestris pv. phaseoli was found to be due to the secretion and subsequent oxidation of homogentisic acid (2, 5-dihydroxyphenylacetic acid) rather than tyrosinase activity as previously reported. Homogentisic acid is an intermediate in tyrosine catabolism for a number of bacteria. Brown-pigmented strains appeared to be disrupted in tyrosine catabolism and could not use tyrosine as a nutrient. Nonpigmented strains, however, could utilize tyrosine as a nutrient, and although they secreted homogentisic acid, the levels were approximately 1/100th that of brown-pigmented strains. Production of brown pigment was stimulated by tyrosine and repressed by glucose. Growth in glucose resulted in a drop in the pH of the media, and the greatest pigment formation was associated with a shift to alkaline conditions in the culture media. By buffering the media near pH 7.0, brown pigment formation was repressed, even though unoxidized homogentisic acid accumulated in the culture media. The disruption of tyrosine catabolism corresponds to other reports describing differences between brown-pigmented and nonpigmented strains, and provides further support for the retention of a special taxonomic status for the brown-pigmented strains.Key words: homogentisic acid, pigments, Xanthomonas, fuscans.

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Secchi, Christian, Marco Orecchioni, Marissa Carta, Francesco Galimi, Francesco Turrini, and Antonella Pantaleo. "Signaling Response to Transient Redox Stress in Human Isolated T Cells: Molecular Sensor Role of Syk Kinase and Functional Involvement of IL2 Receptor and L-Selectine." Sensors 20, no. 2 (January 14, 2020): 466. http://dx.doi.org/10.3390/s20020466.

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Reactive oxygen species (ROS) are central effectors of inflammation and play a key role in cell signaling. Previous reports have described an association between oxidative events and the modulation of innate immunity. However, the role of redox signaling in adaptive immunity is still not well understood. This work is based on a novel investigation of diamide, a specific oxidant of sulfhydryl groups, and it is the first performed in purified T cell tyrosine phosphorylation signaling. Our data show that ex vivo T cells respond to –SH group oxidation with a distinctive tyrosine phosphorylation response and that these events elicit specific cellular responses. The expression of two essential T-cell receptors, CD25 and CD62L, and T-cell cytokine release is also affected in a specific way. Experiments with Syk inhibitors indicate a major contribution of this kinase in these phenomena. This pilot work confirms the presence of crosstalk between oxidation of cysteine residues and tyrosine phosphorylation changes, resulting in a series of functional events in freshly isolated T cells. Our experiments show a novel role of Syk inhibitors in applying their anti-inflammatory action through the inhibition of a ROS-generated reaction.

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Matienko, Ludmila, Vladimir Binyukov, Elena Mil, and Alexander Goloshchapov. "Role of PhOH and Tyrosine in Selective Oxidation of Hydrocarbons." Catalysts 11, no. 9 (August 26, 2021): 1032. http://dx.doi.org/10.3390/catal11091032.

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Earlier, we established that nickel or iron heteroligand complexes, which include PhOH (nickel complexes) or tyrosine residue (nickel or iron complexes), are not only hydrocarbon oxidation catalysts (in the case of PhOH), but also simulate the active centers of enzymes (PhOH, tyrosine). The AFM method established the self-organization of nickel or iron heteroligand complexes, which included tyrosine residue or PhOH, into supramolecular structures on a modified silicon surface. Supramolecular structures were formed as a result of H-bonds and other non-covalent intermolecular interactions and, to a certain extent, reflected the structures involved in the mechanisms of reactions of homogeneous and enzymatic catalysis. Using the AFM method, we obtained evidence at the model level in favor of the involvement of the tyrosine fragment as one of the possible regulatory factors in the functioning of Ni(Fe)ARD dioxygenases or monooxygenases of the family of cytochrome P450. The principles of actions of these oxygenases were used to create highly efficient catalytic systems for the oxidation of hydrocarbons.

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43

Gong, Sheng Zhao. "Kinetics of Inhibition Effect of 4-hydroxy-3-methoxybenzoic acid on Mushroom Tyrosinase." Advanced Materials Research 641-642 (January 2013): 967–70. http://dx.doi.org/10.4028/www.scientific.net/amr.641-642.967.

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A study on the kinetics of inhibitory effect of 4-hydroxy-3-methoxybenzoic acid on the monophenol- and diphenol-oxidation activity of mushroom tyrosinase has been carried out using enzymological kinetic analysis method in a Na2HPO4-NaH2PO4 buffer solution (pH=6.8) at 30 °C. The results show that 4-hydroxy-3-methoxybenzoic acid efficiently can inhibit both monophenol- and diphenol-oxidation activity of mushroom tyrosinase under experiment conditions. Concentrations of 4-hydroxy-3-methoxybenzoic acid leading to 50 % inhibition rate (IC50) on monophenol- and diphenol-oxidation activity were calculated to be 1.3 mmol/L and 2.6 mmol/L respectively, which are lower than that of arbutin (IC50 = 5.3 mmol/L for diphenol-oxidation activity). The presence of 4-hydroxy-3-methoxybenzoic acid also prolongs the lag period in oxidation of L-tyrosine via tyrosinase — A 4.7-minute lagging was observed in the presence of 4 mmol/L 4-hydroxy-3- methoxybenzoic acid, compared to a 1.1-minute lagging in the absence of inhibitor. The inhibition kinetics analyzed by Lineweaver-Burk plots found 4-hydroxy-3- methoxybenzoic acid to be a mixed-type inhibitor for the oxidation of L-DOPA, the equilibrium constants for inhibitor binding with free enzyme, KI , and with enzyme-substract complex, ＫIS, were 1.76 mmol/L and 8.57mmol/L respectively.

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Zheng, Kai, Diya Ren, Y. John Wang, Wayne Lilyestrom, Thomas Scherer, Justin K. Y. Hong, and Junyan A. Ji. "Monoclonal Antibody Aggregation Associated with Free Radical Induced Oxidation." International Journal of Molecular Sciences 22, no. 8 (April 12, 2021): 3952. http://dx.doi.org/10.3390/ijms22083952.

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Oxidation is an important degradation pathway of protein drugs. The susceptibility to oxidation is a common concern for therapeutic proteins as it may impact product efficacy and patient safety. In this work, we used 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH) as an oxidative stress reagent to evaluate the oxidation of therapeutic antibodies. In addition to the oxidation of methionine (Met) and tryptophan (Trp) residues, we also observed an increase of protein aggregation. Size-exclusion chromatography and multi-angle light scattering showed that the soluble aggregates induced by AAPH consist of dimer, tetramer, and higher-order aggregate species. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that inter-molecular disulfide bonds contributed to the protein aggregation. Furthermore, intrinsic fluorescence spectra suggested that dimerization of tyrosine (Tyr) residues could account for the non-reducible cross-links. An excipient screening study demonstrated that Trp, pyridoxine, or Tyr could effectively reduce protein aggregation due to oxidative stress. This work provides valuable insight into the mechanisms of oxidative-stress induced protein aggregation, as well as strategies to minimize such aggregate formation during the development and storage of therapeutic proteins.

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45

MORTON, Lincoln W., Ian B. PUDDEY, and Kevin D. CROFT. "Comparison of nitration and oxidation of tyrosine in advanced human carotid plaque proteins." Biochemical Journal 370, no. 1 (February 15, 2003): 339–44. http://dx.doi.org/10.1042/bj20020964.

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The importance of reactive nitrogen species in atherosclerosis remains poorly understood, despite the semi-quantitative evidence for the presence of 3-nitrotyrosine provided by immunohistochemical staining studies. At this time, there appear to be no data describing the prevalence of nitration relative to oxidation in atherosclerotic plaque proteins. The present study used 3-nitrotyrosine and dityrosine as markers of nitration and oxidation respectively to examine the relative abundance of each process. Substantial methodological improvements were required to overcome problems associated with sensitivity and artefactual production of 3-nitrotyrosine when quantified by GLC-MS. It was shown that careful selection of hydrolysis vessel, sample reduction and the use of the oxazolinone derivative provided sample stability and exquisite sensitivity. Using these methods, it was observed that the frequency of nitration was 92±15μmol/mol of tyrosine (0.01%). Dityrosine was present at 1.5±0.14mmol/mol of tyrosine (0.30%) using HPLC/fluorescence; thus nitration accounted for approx. 3% of the tyrosine modifications measured. Given that other modifications of tyrosine are known to occur in carotid plaque proteins, the contribution of nitration to the total pool of modified tyrosine is very small. However, the possibility of metabolic processes or chemical agents modifying 3-nitrotyrosine to secondary oxidation products remains an alternative explanation for the low levels demonstrated in this study.

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Bartesaghi⁎, S., L. Folkes, M. Trujillo, P. Wardman, and R. Radi. "Kinetics of oxidation of tyrosine by a model alkoxyl radical: relevance to the connection between lipid peroxidation and protein tyrosine oxidation." Free Radical Biology and Medicine 53 (September 2012): S258. http://dx.doi.org/10.1016/j.freeradbiomed.2012.08.057.

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47

Odeniyi, Olubusola Ayoola, Adebosola Ogunsanya, and John Onolame Unuofin. "Optimization and Characterization of Tyrosinases from Multi-enzyme Producing Fusarium solani and Fumago sp." Periodica Polytechnica Chemical Engineering 63, no. 4 (May 30, 2019): 582–90. http://dx.doi.org/10.3311/ppch.13719.

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Tyrosinase is a copper-containing metalloprotein that catalyzes the oxidation of tyrosine, in particular, L-DOPA to L-Dopaquinone, which are precursors of brown pigments in some wounded eukaryotic tissues. The present study focused on screening, production and characterization of tyrosinase from multi-enzyme producing Fusarium solani B1 and Fumago sp. A total of 25 strains were isolated from rotting wood samples and screened for hydrolytic and oxidative multi-enzyme potentials using different polymeric substrates. The two most consistent strains: Fusarium solani B1 and Fumago sp. B13 were further evaluated for tyrosinase production. Some media cultural parameters and physiological conditions were optimized in order to maximize tyrosinase production. Incubation of Fumago sp. B13 and Fusarium solani B1 for 96 and 144 h in medium containing 2 % and 0.2 % ratios of Glucose and NaNO3 with pH 6 and 7, respectively, was most suitable for tyrosinase production. Characterization of the partially purified tyrosinase from Fumago sp. B13 and Fusarium solani B1 exhibited optimal activities at pH 6-7, 30 °C, and 1 mM Cu2+, respectively, thereby suggesting their potentials for novel biotechnological applications.

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48

Krajnik, P., R. M. Quint, S. Solar, N. Getoff, and G. Sontag. "Influence of Temperature and Oxygen Concentration on the Radiation Induced Oxidation of Phenylalanine." Zeitschrift für Naturforschung A 50, no. 9 (September 1, 1995): 864–70. http://dx.doi.org/10.1515/zna-1995-0912.

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AbstractThe formation of tyrosine isomers by γ-radiolysis of neutral aqueous phenylalanine solutions was found to be strongly dependent on oxygen concentration and temperature. Changing the dose rate did not influence the degradation process. In the presence of 0.25 x 10-3 mol dm-3 oxygen at room temperature the yields of o-tyrosine as well as of m- and p-tyrosine drop from G(o-Tyr) = 0.5 and G(m-Tyr) = G(p-Tyr) = 0.4 at a dose of 0.3 kGy to 0.18 and 0.16 at 2.5 kGy, respectively. In solutions containing 1.25 x 10-3 mol dm-3 oxygen the initial yields remain unchanged but decrease at 2.5 kGy only to G(o-Tyr) = 0.3 and G(m-Tyr) = G(p-Tyr) = 0.20. Under the latter reaction conditions also 3,4-dihydroxyphenylalanine was found.Samples irradiated in frozen state did not show remarkable radiolysis of phenylalanine and tyrosine formation. In the range between 5 and 20°C no essential influence of temperature on the phenylalanine radiolysis and tyrosine yields was observable. The obtained results are important for methods using the tyrosine yields as markers for the detection of irradiated food. Storage conditions and irradiation temperature play an essential role on radiation induced changes of food.

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Neyra Recky, Jael R., Mariana P. Serrano, M. Laura Dántola, and Carolina Lorente. "Oxidation of tyrosine: Antioxidant mechanism of l-DOPA disclosed." Free Radical Biology and Medicine 165 (March 2021): 360–67. http://dx.doi.org/10.1016/j.freeradbiomed.2021.01.037.

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Castaño, Carolina, María L. Dántola, Esther Oliveros, Andrés H. Thomas, and Carolina Lorente. "Oxidation of Tyrosine Photoinduced by Pterin in Aqueous Solution." Photochemistry and Photobiology 89, no. 6 (June 27, 2013): 1448–55. http://dx.doi.org/10.1111/php.12099.

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