title: Inhibitory effects of 4-vinylbenzaldehyde and 4-vinylbenzoic acid on the activity of mushroom tyrosinase.
abstract: Tyrosinase (EC 1.14.18.1) catalyzes both the hydroxylation of tyrosine into o-diphenols and the oxidation of o-diphenols into o-quinones which form brown or black pigments. Here, the inhibitory effects of 4-vinylbenzaldehyde and 4-vinylbenzoic acid on the activity of mushroom tyrosinase have been investigated. The results showed that both 4-vinylbenzaldehyde and 4-vinylbenzoic acid could inhibit both monophenolase activity and diphenolase activity of the enzyme. For the monophenolase activity, 4-vinylbenzoic acid could lengthen the lag time, but 4-vinylbenzaldehyde could not. Both 4-vinylbenzaldehyde and 4-vinylbenzoic acid decreased the steady-state activity, and the IC50 values were estimated as 93 microM and 3.0 mM for monophenolase activity, respectively. For the diphenolase activity, the inhibitory capacity of 4-vinylbenzaldehyde was stronger than that of 4-vinylbenzoic acid, and the IC50 values were estimated as 23 microM and 0.33 mM, respectively. Kinetic analyses showed that inhibition by both compounds was reversible and their mechanisms were mixed-II type; their inhibition constants were also determined and compared.
authors.affiliation: The key Laboratory of Ministry of Education for Cell Biology and Tumor Cell Engineering, School of Life Sciences, Xiamen University, Xiamen 361005, P R China.
authors.forename: Kang-Kang
authors.initials: KK
authors.lastname: Song
authors.forename: Qing-Xi
authors.initials: QX
authors.lastname: Chen
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.forename: Ling
authors.initials: L
authors.lastname: Qiu
authors.forename: Huang
authors.initials: H
authors.lastname: Huang
mesh_terms: D000363:Agaricales; D001547:Benzaldehydes / Q000494:pharmacology*; D002384:Catalysis; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000378:metabolism*; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000493:pharmacokinetics; D010088:Oxidoreductases / Q000378:metabolism; D013343:Styrenes / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D001547:Benzaldehydes; D004791:Enzyme Inhibitors; D013343:Styrenes; D010088:Oxidoreductases; C412191:monophenolase; D014442:Monophenol Monooxygenase; C105064:4-vinylbenzoic acid