桑黄素对蘑菇酪氨酸酶的抑制作用  

Inhibitory Effects of Morin on Mushroom Tyrosinase

作　　者：陈桂霞[1] 邱凌[1] 宋康康[1] 陈祥仁[1] 陈清西[1] 

机构地区：[1]厦门大学生命科学学院细胞生物学与肿瘤细胞工程教育部重点实验室,福建厦门361005

出　　处：《厦门大学学报（自然科学版）》2006年第3期424-427,共4页Journal of Xiamen University：Natural Science

基　　金：福建省科技攻关课题(2004N002);福建省自然科学基金(B0410003);国家自然科学基金(30570408)资助

摘　　要：研究桑黄素(Morin)对蘑菇酪氨酸酶单酚酶和二酚酶活力的影响和抑制效应的结果表明:桑黄素对蘑菇酪氨酸酶的单酚酶和二酚酶活性均有抑制作用;导致单酚酶活力和二酚酶活力下降50%的抑制剂浓度(IC50)分别为0.08和1.02mmol/L;桑黄素对蘑菇酪氨酸酶的单酚酶的迟滞时间有明显的延长效应,0.175 mmol/L桑黄素使得单酚酶的迟滞时间从24 s延长到362 s,迟滞时间增加了14倍,酶的稳态活力下降了61.9%;桑黄素对二酚酶的抑制作用表现为竞争性可逆抑制作用,抑制常数为0.55 mmol/L.Tyrosinase （1.14.18.1） is a metalloenzyme oxidase which catalyzes two distinct reactions of melanin synthesis., the hydroxylation of a monophenol and the oxidation of o-diphenol to the corresponding o-quinone. In this paper,we find that Morin has potent inhibitory effects on the monophenolase and o-diphenolase activity of mushroom tyrosinase. The inhibition kinetics and mechanism of this compound on the enzyme were further studied. The results showed that the inhibition of Morin was a reversible reaction with remaining enzyme activity. The inhibitor concentrations leading to 50% （IC50） activity lost were estimated to be 0. 08 mmol/L for monophenolase activity and 1.02 mmol/L for diphenolase, respectively. Morin can extend the lag time of mushroom tyrosinase for oxidation of L-tyrosine,and it led to extending the lag time from 24 s to 362 s when its concentration was at 0. 175 mmoL/L. The inhibition kinetics analyzed by Lineweaver-Burk plots showed that Morin was a competitive inhibitor to the enzyme for the oxidation of LDOPA,and the inhibition constant was determined to be 0.55 mmol/L.

关 键 词：蘑菇酪氨酸酶 单酚酶活性 二酚酶活性 桑黄素 抑制机理 

分 类 号：Q356.1[生物学—遗传学]