Isotope effects in mechanistic studies of l-tyrosine halogen derivatives hydroxylation catalyzed by tyrosinase
نویسندگان
چکیده
The kinetic (KIE) and solvent (SIE) isotope effect methods were used to investigate the mechanism of enzymatic hydroxylation of halogenated derivatives of l-tyrosine to l-DOPA catalyzed by the enzyme tyrosinase (EC 1.14.18.1). The values of deuterium KIE and SIE were obtained using the non-competitive method with spectrophotometric measurements. The Lineweaver-Burk plots were used for determination of the inhibition mode of 3'-iodo-l-tyrosine. Based upon kinetic effects values the mechanism of action of enzyme tyrosinase was proposed.
منابع مشابه
Melanins are pigments responsible for skin and hair fol- licles pigmentation in mammals. Melanin biosynthesis or melanogenesis occurs in specialized organelles, called melanosomes, through a cascade of enzymatic reactions
licles pigmentation in mammals. Melanin biosynthesis or melanogenesis occurs in specialized organelles, called melanosomes, through a cascade of enzymatic reactions using the amino acid tyrosine as the initial substrate. The first two steps in the biosynthetic pathway, hydroxylation of tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA) and oxidation of L-DOPA to dopaquinone, are catalyzed by tyr...
متن کاملThe Anti-melanogenesis Activities of Some Selected Red Macroalgae from Northern Coasts of the Persian Gulf
Tyrosinase is a key enzyme in melanin production. Therefore, tyrosinase inhibitors are used in cosmetic and medicinal industries to prevent or treat overproduction of melanin such as melasma, solar lentigo and post inflammatory melanoderma. Due to safety of natural whitening agents, in the present study, in-vitro anti-tyrosinase and in-vivo anti-melanogenesis activities of some selected red mac...
متن کاملThe Anti-melanogenesis Activities of Some Selected Red Macroalgae from Northern Coasts of the Persian Gulf
Tyrosinase is a key enzyme in melanin production. Therefore, tyrosinase inhibitors are used in cosmetic and medicinal industries to prevent or treat overproduction of melanin such as melasma, solar lentigo and post inflammatory melanoderma. Due to safety of natural whitening agents, in the present study, in-vitro anti-tyrosinase and in-vivo anti-melanogenesis activities of some selected red mac...
متن کاملTyrosinase inhibition kinetics of anisic acid.
Anisic acid (p-methoxybenzoic acid) was characterized as a tyrosinase inhibitor from ani-seed, a common food spice. It inhibited the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by tyrosinase with an IC50 of 0.60 mM. The inhibition of tyrosinase by anisic acid is a reversible reaction with residual enzyme activity. This phenolic acid was found to be a classical noncompetitive in...
متن کاملKojic acid-derived tyrosinase inhibitors: synthesis and bioactivity
Tyrosinase is a key enzyme for melanin biosynthesis, catalyzing the oxidation of L-tyrosine to L-dopaquinone. The tyrosinase inhibition is an effective approach to control hyperpigmentation in human skin and enzymatic browning in fruits and vegetables. Kojic acid is a naturally-occurring tyrosinase inhibitor which has been clinically used to treat the hyperpigmentation of skin. However, kojic a...
متن کامل