4-HR与抗坏血酸对中华管鞭虾多酚氧化酶的抑制动力学模拟分析

研究无硫复合抑制剂主要作用成分4-己基间苯二酚（4-hexylresorcinol，4-HR）、抗坏血酸对中华管鞭虾多酚氧化酶（polyphenoloxidase，PPO）活性的抑制作用，并从抑制剂化学结构及动力学模型出发分析推断其抑制机理。结果表明，4-HR、抗坏血酸均能抑制PPO活力，且对酶促反应有延滞作用，两者半抑制浓度分别为0.072、2.02?mmol/L，对中华管鞭虾PPO的抑制作用都表现为竞争性抑制；化学动力学模拟分析显示4-HR、抗坏血酸均可与PPO双铜活性中心结合，其中4-HR可生成一种高稳定的多酚氧化酶络合物，持续有效地消耗PPO。4-HR、抗坏血酸均能有效抑制中华管鞭虾PPO酶促反应，其中4-HR抑制效果更显著。本实验为无硫复合抑制剂在海水虾捕捞与加工过程中的应用推广提供理论依据。

Kinetic Analysis of the Inhibitory Effect of 4-Hexylresorcinol and Ascorbic Acid on Polyphenoloxidase from Solenocera crassicornis

The purpose of this study was to investigate the inhibitory effects of 4-hexylresorcinol (4-HR) and ascorbic acid (AA) on the activity of purified polyphenoloxidase (PPO) from Solenocera crassicornis. In addition, the inhibitory mechanism was elucidated through kinetic modelling with respect to the structures of the inhibitors. The results showed that both 4-HR and AA could significantly inhibit PPO activity with a half-maximal inhibitory concentration (IC50) of 0.072 and 2.02 mmol/L, respectively and provoke a lag period for the enzymatic reaction. Each of the two compounds exerted competitive inhibition on PPO activity. The kinetic analysis indicated that both 4-HR and AA could be combined with the di-copper binding active center of PPO. 4-HR could consume PPO continuously and effectively by forming a highly stable complex. In conclusion, both 4-HR and AA have been shown to be effective in controlling the enzymatic reaction rate of PPO, 4-HR being stronger than AA. This result provides theoretical support for the application of sulfur-free 4-HR-AA composite preservative in the catching and processing of shrimp.