苯甲醛族化合物抑制蘑菇酪氨酸酶活力的研究

Studies on Mushroom Tyrosinase Activity Inhibited by Benzaldehyde Family Compounds

报道几种苯甲醛族化合物对蘑菇酪氨酸酶催化L 多巴氧化反应活力的影响以及抑制作用机理.研究结果表明,苯甲醛族化合物对酶的效应表现为可逆抑制作用,苯甲醛及其m 和p 甲氧基取代物表现为非竞争性抑制,而o 位、m 位和p 位羟基取代物表现为竞争性抑制.通过测定酶活力下降50%的抑制剂浓度(IC50)和抑制常数来比较抑制剂作用的强度,探讨不同取代基团对抑制作用的影响.提出抑制剂与酶分子的作用模型.

Tyrosinase (1.14.18.1) is a metalloenzyme oxidase which catalyzes two distinct reactions of melanin synthesisthe hydroxylation of a monophenol and the oxidation of odiphenol to the corresponding oquinone. Lots of benzaldehyde family can inhibit the enzyme activity for the oxidation of LDOPA. In the present paper, the inhibition kinetics and mechanism of benzaldehyde family compounds on the enzyme for the oxidation of LDOPA were studied. The results show that the inhibition of tyrosinase by benzaldehyde family is a reversible reaction with remaining enzyme activity. The inhibitory mechanism of benzaldehyde, mmethoxybenzaldehyde and pmethoxybenzaldehyde belongs to being noncompetitive while that of ohydroxybenzaldehyde, mhydroxybenzaldehyde and phydroxybenzaldehyde belongs to being competitive. The equilibrium constants for those inhibitors binding with the enzyme were determined.