通过测定酶的稳态活力、迟滞时间和动力学参数,研究对香豆酸、阿魏酸及低聚糖阿魏酸酯对酪氨酸酶的抑制效果。结果表明,3种物质对酪氨酸酶单酚酶活性均有抑制作用,其中对香豆酸的抑制作用最强,其次为低聚糖阿魏酸酯和阿魏酸。对香豆酸、低聚糖阿魏酸酯和阿魏酸对单酚酶的IC 50值分别为0.75,3.20,9.30 mmol/L。对香豆酸和阿魏酸抑制二酚酶活性,IC 50值分别为4.3,12.7 mmol/L；但低聚糖阿魏酸酯对二酚酶活力没有影响。对香豆酸能明显延长单酚酶反应的迟滞时间,阿魏酸影响很小,而低聚糖阿魏酸酯则缩短迟滞时间。动力学研究结果显示,阿魏酸和低聚糖阿魏酸酯对单酚酶的抑制作用表现为混合性抑制,而对香豆酸为竞争性抑制。%This study investigated the inhibitory effects of p-coumaric acid,ferulic acid and feruloylated oligosaccharides on catalytic activi-ties of tyrosinase by analysising tyrosinase steady state activity and enzyme kinetics.The results showed that the three compounds were found to efficiently inhibit tyrosinase monophenolase activities.The p-Coumaric acid was the strongest inhibitor followed by feruloylated oligosaccharides and ferulic acid,with the IC 50 value of 0.75,3.20, 9.30 mmol/L respectively.Moreover,p-coumaric acid and ferulic acid were found to inhibit the activities of diphenolase with IC 50 value of 4.3,12.7 mmol/L respectively;however,feruloylated oligosac-charides showed no inhibitory effect on diphenolase activity.p-Cou-maric acid increased the lag time of monophenolase activity,but fer-ulic acid showed little effect;while feruloylated oligosaccharides re-duced the lag time of monophenolase activity.Enzyme kinetics analy-sis indicated that p-coumaric acid is a competitive inhibitor of the monophenolase,while ferulic acid and feruloylated oligosaccharides showed a mixed inhibitory effect.
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