Premium
EFFECT OF BENZOIC ACID AND SOME OF ITS DERIVATIVES ON THE RATE OF DL‐DOPA OXIDATION BY MUSHROOM TYROSINASE 1
Author(s) -
KAHN VARDA,
BENSHALOM NOACH,
ZAKIN VARDA
Publication year - 1997
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1997.tb00219.x
Subject(s) - chemistry , benzoic acid , tyrosinase , salicylic acid , vanillic acid , hydroxylation , hydroxybenzoic acid , organic chemistry , medicinal chemistry , biochemistry , enzyme
Vanillic acid and salicylic acid inhibited the rate of dihydroxyphenylalanine (DL‐DOPA) oxidation to dopachrome (γ max = 475 nm) by tyrosinase at all concentrations tested. Benzoic acid and p‐hydroxybenzoic acid (PHBA), at relatively low concentrations, slightly stimulated the rate of DL‐DOPA oxidation, whereas at higher concentrations each inhibited the reaction. p‐Hydroxybenzoic acid methyl ester (PHBAME), at relatively low concentrations, had a pronounced synergistic effect on the reaction, whereas at relatively high concentrations it inhibited the rate of DL‐DOPA oxidation. The synergistic effect of 1.6–6.6 mM PHBAME on the rate of DL‐DOPA oxidation to dopachrome was found to be only an apparent effect due to the ability of PHBAME to be hydroxylated very slowly by tyrosinase to a yellow pigmented product(s) with DL‐DOPA serving as a reductant (AH 2 ) for the hydroxylation reaction, thus hastening the conversion of PHBAME to pigmented product(s). Vanillic acid, salicylic acid, benzoic acid and PHBA could not be hydroxylated by tyrosinase.