[PMID]: | 28493937 |
[Au] Autor: | Garcia-Jimenez A; Teruel-Puche JA; Berna J; Rodriguez-Lopez JN; Tudela J; Garcia-Canovas F |
[Ad] Endereço: | GENZ-Group of research on Enzymology, Department of Biochemistry and Molecular Biology-A, Regional Campus of International Excellence "Campus Mare Nostrum", University of Murcia, Espinardo, Murcia, Spain. |
[Ti] Título: | Action of tyrosinase on alpha and beta-arbutin: A kinetic study. |
[So] Source: | PLoS One;12(5):e0177330, 2017. |
[Is] ISSN: | 1932-6203 |
[Cp] País de publicação: | United States |
[La] Idioma: | eng |
[Ab] Resumo: | The known derivatives from hydroquinone, α and ß-arbutin, are used as depigmenting agents. In this work, we demonstrate that the oxy form of tyrosinase (oxytyrosinase) hydroxylates α and ß-arbutin in ortho position of the phenolic hydroxyl group, giving rise to a complex formed by met-tyrosinase with the hydroxylated α or ß-arbutin. This complex could evolve in two ways: by oxidizing the originated o-diphenol to o-quinone and deoxy-tyrosinase, or by delivering the o-diphenol and met-tyrosinase to the medium, which would produce the self-activation of the system. Note that the quinones generated in both cases are unstable, so the catalysis cannot be studied quantitatively. However, if 3-methyl-2-benzothiazolinone hydrazone hydrochloride hydrate is used, the o-quinone is attacked, so that it becomes an adduct, which can be oxidized by another molecule of o-quinone, generating o-diphenol in the medium. In this way, the system reaches the steady state and originates a chromophore, which, in turn, has a high absorptivity in the visible spectrum. This reaction allowed us to characterize α and ß-arbutin kinetically as substrates of tyrosinase for the first time, obtaining a Michaelis constant values of 6.5 ± 0.58 mM and 3 ± 0.19 mM, respectively. The data agree with those from docking studies that showed that the enzyme has a higher affinity for ß-arbutin. Moreover, the catalytic constants obtained by the kinetic studies (catalytic constant = 4.43 ± 0.33 s-1 and 3.7 ± 0.29 s-1 for α and ß-arbutin respectively) agree with our forecast based on 13 C NMR considerations. This kinetic characterization of α and ß-arbutin as substrates of tyrosinase should be taken into account to explain possible adverse effects of these compounds. |
[Mh] Termos MeSH primário: |
Arbutina/farmacologia Monofenol Mono-Oxigenase/metabolismo
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[Mh] Termos MeSH secundário: |
Agaricales/enzimologia Arbutina/química Benzotiazóis/farmacologia Inibidores Enzimáticos/farmacologia Hidrazonas/farmacologia Peróxido de Hidrogênio/farmacologia Cinética Simulação de Acoplamento Molecular Monofenol Mono-Oxigenase/antagonistas & inibidores Consumo de Oxigênio/efeitos dos fármacos Especificidade por Substrato/efeitos dos fármacos Fatores de Tempo
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[Pt] Tipo de publicação: | JOURNAL ARTICLE |
[Nm] Nome de substância:
| 0 (Benzothiazoles); 0 (Enzyme Inhibitors); 0 (Hydrazones); BBX060AN9V (Hydrogen Peroxide); C5INA23HXF (Arbutin); EC 1.14.18.1 (Monophenol Monooxygenase); OZ2685O88C (3-methyl-2-benzothiazolone hydrazone) |
[Em] Mês de entrada: | 1709 |
[Cu] Atualização por classe: | 171116 |
[Lr] Data última revisão:
| 171116 |
[Sb] Subgrupo de revista: | IM |
[Da] Data de entrada para processamento: | 170512 |
[St] Status: | MEDLINE |
[do] DOI: | 10.1371/journal.pone.0177330 |
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