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Peng L, Wang C, Li P, Cheng B, Hu Y, Cheng Y, Zheng Q. Evaluation of hypopigmentation in embryonic zebrafish induced by emerging disinfection byproduct, 3, 5-di-I-tyrosylalanine. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 225:105525. [PMID: 32629302 DOI: 10.1016/j.aquatox.2020.105525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/28/2020] [Accepted: 05/30/2020] [Indexed: 06/11/2023]
Abstract
Halogenated dipeptides, 3, 5-di-I-tyrosylalanine (DIYA), have been identified as novel disinfection byproducts (DBPs), following chloramination of authentic water. However, little is known about their toxicity. Zebrafish embryos were used to assess the toxicity of novel iodinated DBPs (I-DBPs). Although DIYA did not exhibit high acute toxicity to embryonic zebrafish (LC50 > 2 mM), it significantly inhibited pigmentation of melanophores and xanthophores on head, trunk and tail at 500 μM as determined by photographic analysis. Whereas N-phenylthiourea (PTU) as a pigment inhibitor did not inhibit development of yellow pigments. Colorimetric detection of melanin further confirmed these results. Quantitative real time polymerase chain reaction (qRT-PCR) measurements indicated that genes (dct, slc24a5, tyr, tyrp1a, tyrp1b, silva) associated with the melanogenesis pathway were dramatically down-regulated following exposure to 500 μM DIYA. In addition, enzymatic activity of tyrosinase (TYR) decreased, also demonstrating that the underlying mechanism of hypopigmentation was attributed to the disruption of melanogenesis pathway. Transcription levels of xanthophore genes (gch2, bnc2, csf1a, csf1b, pax7a and pax7b) were also monitored by qRT-PCR assay. DIYA exposure up-regulated expression of gch2 and bnc2, but not csf1 and pax7. Tested DIYA analogues, brominated tyrosine was unlikely to inhibit pigmentation, indicating that the iodine substitution and dipeptides structure are of important structural feature for the inhibition of pigmentation. In this study, we observed that DIYA inhibited melanogenesis related genes, which might contribute to pigmentation defects. Moreover, as an emerging I-DBPs, the developmental toxicity of aromatic dipeptides should be further studied.
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Affiliation(s)
- Lei Peng
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China; School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430025, China
| | - Chang Wang
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China.
| | - Pingdeng Li
- Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Institute of Environment and Health, Jianghan University, Wuhan 430056, China; School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430025, China
| | - Bo Cheng
- School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430025, China
| | - Yeli Hu
- School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430025, China
| | - Yang Cheng
- School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
| | - Qi Zheng
- Key Laboratory of Optoelectronic Chemical Materials and Devices, Jianghan University, Wuhan 430056, China.
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Rolff M, Schottenheim J, Tuczek F. Monooxygenation of external phenolic substrates in small-molecule dicopper complexes: implications on the reaction mechanism of tyrosinase. J COORD CHEM 2010. [DOI: 10.1080/00958972.2010.503273] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Malte Rolff
- a Institut für Anorganische Chemie, Christian Albrechts Universität Kiel , Max-Eyth-Straße 2, D-24118 Kiel, Germany
| | - Julia Schottenheim
- a Institut für Anorganische Chemie, Christian Albrechts Universität Kiel , Max-Eyth-Straße 2, D-24118 Kiel, Germany
| | - Felix Tuczek
- a Institut für Anorganische Chemie, Christian Albrechts Universität Kiel , Max-Eyth-Straße 2, D-24118 Kiel, Germany
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Tepper AWJW, Bubacco L, Canters GW. Stopped-flow Fluorescence Studies of Inhibitor Binding to Tyrosinase from Streptomyces antibioticus. J Biol Chem 2004; 279:13425-34. [PMID: 14699163 DOI: 10.1074/jbc.m309367200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tyrosinase (Ty) is a type 3 copper protein involved in the rate-limiting step of melanin synthesis. It is shown that the endogenous Trp fluorescence of tyrosinase from Streptomyces antibioticus is remarkably sensitive to the redox state. The fluorescence emission intensity of the [(Cu(I) Cu(I)] reduced species is more than twice that of the oxygen-bound [Cu(II)-O(2)(2-)-Cu(II)] form. The emission intensity of the oxidized [Cu(II)-OH(-)-Cu(II)] protein (Ty(met)) appears to be dependent on an acid-base equilibrium with a pK(a) value of 4.5 +/- 0.1. The binding of fluoride was studied under pseudo first-order conditions using stopped-flow fluorescence spectroscopy. The kinetic parameters k(on), K(d), and the fraction of fluorescence emission quenched upon fluoride binding show a similar pH dependence as above with an average pK(a) value of 4.62 +/- 0.05. Both observations are related to the dissociation of Cu(2)-bridging hydroxide at low pH. It is further shown that Ty is rapidly inactivated at low pH and that halide protects the enzyme from this inactivation. All results support the hypothesis that halide displaces hydroxide as the Cu(2)-bridging ligand in Ty(met). The relevance of the experimental findings for the catalytic cycle is discussed. The data are consistent with the data obtained from other techniques, validating the use of fluorescence quenching as a sensitive and effective tool in studying ligand binding and substrate conversion.
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Affiliation(s)
- Armand W J W Tepper
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
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Tepper AWJW, Bubacco L, Canters GW. Structural basis and mechanism of the inhibition of the type-3 copper protein tyrosinase from Streptomyces antibioticus by halide ions. J Biol Chem 2002; 277:30436-44. [PMID: 12048185 DOI: 10.1074/jbc.m202461200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The inhibition of the type-3 copper enzyme tyrosinase by halide ions was studied by kinetic and paramagnetic (1)H NMR methods. All halides are inhibitors in the conversion of l-3,4-dihydroxyphenylalanine (l-DOPA) with apparent inhibition constants that follow the order I(-) < F(-) << Cl(-) < Br(-) at pH 6.80. The results show that the inhibition arises from the interaction of halide with both the oxidized (affinity F(-) > Cl(-) > Br(-) >> I(-)) and reduced (affinity I(-) > Br(-) > Cl(-) >> F(-)) enzyme. The paramagnetic (1)H NMR of the oxidized enzyme complexed with the halides is consistent with a direct interaction of halide with the type-3 site and shows that the (Cu-His(3))(2) coordination occurs in all halide-bound species. It is surmised that halides bridge both of the copper ions in the active site. Fluoride and chloride are shown to bind only to the low pH form of oxidized tyrosinase, explaining the strong pH dependence of the inhibition by these ions. We further show that p-toluic acid and the bidentate transition state analogue, Kojic acid, displace chloride from the oxidized active site, whereas the monodentate substrate analogue, p-nitrophenol, forms a ternary complex with the enzyme and the chloride ion. On the basis of the experimental results, a model is formulated for the inhibitor action and for the reaction of diphenols with the oxidized enzyme.
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Affiliation(s)
- Armand W J W Tepper
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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5
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Nicolas JJ, Richard-Forget FC, Goupy PM, Amiot MJ, Aubert SY. Enzymatic browning reactions in apple and apple products. Crit Rev Food Sci Nutr 1994; 34:109-57. [PMID: 8011143 DOI: 10.1080/10408399409527653] [Citation(s) in RCA: 318] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This review examines the parameters of enzymatic browning in apple and apple products that is, phenolic compounds, polyphenoloxidases, and other factors (ascorbic acid and peroxidases), both qualitatively and quantitatively. Then the relationships between intensity of browning and the browning parameters are discussed, including a paragraph on the methods used for browning evaluation. Finally, the different methods for the control of browning are presented.
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Affiliation(s)
- J J Nicolas
- Chaire de Biochimie Industrielle et Agro-Alimentaire, Conservatoire National des Arts et Métiers, Paris, France
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Gómez-Skarmeta JL, Peñafiel R, Galindo JD, Lozano JA. Inactivation of ornithine decarboxylase by intermediates of tyrosinase-catalyzed reaction. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1993; 25:353-8. [PMID: 8462726 DOI: 10.1016/0020-711x(93)90624-n] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
1. Intermediates in the process of melanin synthesis formed through oxidation of catechols by tyrosinase produced the inactivation of ornithine decarboxylase (ODC), a key enzyme in the polyamine biosynthesis pathway. 2. The inactivation was dependent on the substrate used (dihydroxybenzylamine > L-3,4-dihydroxyphenylalanine > L-tyrosine) and on the concentration of intermediate produced rather than on the rate of formation. 3. Sulfhydryl compounds (dithiothreitol and glutathione) or quinone-reducing agents (ascorbic acid) prevented the inactivation of ODC; L-ornithine, but not other amino acids, also protected partially ODC. The results suggest that different cysteine residues in ODC molecule are implicated in the inactivatory event. 4. When 14C-labeled catechols were used, numerous polypeptides resulted labeled, showing that the reactive quinones formed as intermediates in the process of melanin biosynthesis bind covalently to many cellular proteins.
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Affiliation(s)
- J L Gómez-Skarmeta
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Murcia, Spain
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Devi CC, Tripathi RK, Ramaiah A. Citrate activates tyrosinase from B-16 murine melanoma and human skin. PIGMENT CELL RESEARCH 1989; 2:117-22. [PMID: 2497449 DOI: 10.1111/j.1600-0749.1989.tb00171.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Citrate stimulates cresolase activity of tyrosinase from B-16 murine melanoma and human skin. Maximal stimulation by citrate was obtained at 2 mM, and stimulation was decreased at higher concentrations. Citrate stimulates tyrosinase not only from mammalian sources but also from mushroom. The stimulation was not due to reversal of inhibition of enzyme activity by excess tyrosine. On rapid decrease in pH of the enzyme solution from 6.8 to 5.0-5.2, the enzyme is no longer inhibited by excess tyrosine even when its activity was assayed at pH 6.8. Citrate also stimulates this form of enzyme. However, the stimulation is more at acidic pH than at pH 6.8. At higher concentrations of citrate the stimulatory effect decreases at both pH 5.0 and pH 6.8. Inhibition of this enzyme occurs at higher concentrations (22 mM) at pH 6.8. The physiological role of stimulation of cresolase activity of tyrosinase by citrate is yet to be unravelled.
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Affiliation(s)
- C C Devi
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
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Tudela J, Garcia-Canovas F, Varón R, Jimenez M, Garcia-Carmona F, Lozano JA. Kinetic characterization of dopamine as a suicide substrate of tyrosinase. JOURNAL OF ENZYME INHIBITION 1987; 2:47-56. [PMID: 3149665 DOI: 10.3109/14756368709030356] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A kinetic study of the inactivation of frog epidermis tyrosinase by a suicide substrate dopamine hydrochloride is described. The kinetic parameters and constants which characterize this reaction have been determined and the effects of pH and the stoichiometric inhibition by chloride have been considered.
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Affiliation(s)
- J Tudela
- Departmento de Bioquimica, Facultad de Medicina, Universidad de Murcia, Spain
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Martinez JH, Solano F, Peñafiel R, Galindo JD, Iborra JL, Lozano JA. Comparative study of tyrosinases from different sources: relationship between halide inhibition and the enzyme active site. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1986; 83:633-6. [PMID: 3082587 DOI: 10.1016/0305-0491(86)90309-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The inhibition of tyrosinases from frog epidermis (Rana esculenta ridibunda), mushroom (Agaricus bisporus) and Harding-Passey mouse melanoma by halides is compared. In all cases, the inhibition is pH dependent, increasing when the pH decreases. The order of inhibition is I- greater than Br- greater than Cl- much greater than F- for frog epidermis tyrosinase, F- greater than I- greater than Cl- greater than Br- for mushroom tyrosinase and F- greater than Cl- much greater than Br- greater than I- for the mouse melanoma enzyme. These results are discussed in terms of the active site accessibility to exogenous ligands. The activation energies of the enzyme-catalysed L-dopa oxidation were also calculated, being the values 6.86, 17.01 and 20.25 kcal/mol for frog epidermis, mushroom and Harding-Passey mouse melanoma, respectively. A relationship between these values and the evolutionary adaptation of these enzymes is proposed.
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11
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Garcia-Borron JC, Solano F, Iborra JL, Lozano JA. Aggregation equilibria of tyrosinase of Harding-Passey mouse melanoma. Biochem J 1985; 228:95-101. [PMID: 3924035 PMCID: PMC1144957 DOI: 10.1042/bj2280095] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The purification of two isoenzymes of tyrosinase has been carried out in Harding-Passey mouse melanoma. One is found in the cytosol and the other one bound to melanosomes. Both migrate as single bands on sodium dodecyl sulphate/polyacrylamide gels, having an apparent Mr of 58 000. Solubilized particulate tyrosinase showed an aggregation equilibrium involving a monomer, tetramer, octamer and a high-Mr micellar form with Brij 35, the solubilizing agent. H.p.l.c. studies indicated a interconversion between those species, the monomer contribution increasing with the sample dilution. The tetramer and the octamer probably represent the predominant forms in vivo. Soluble tyrosinase showed a simpler aggregation equilibrium, involving two forms, monomer and tetramer, with the same interconversion pattern. Fluorescence studies suggested that tryptophan residues were exposed to the aqueous environment when tyrosinase was dissociated by dilution. Tyrosinase shows a tendency to aggregate, at low protein concentration, and a resistance to dissociation by urea or SDS so remarkable that gel-permeation chromatography in 4M-urea does not affect the equilibrium, and the band obtained on SDS/polyacrylamide-gel electrophoresis is a dimer.
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