柿子单宁对几种蛇毒中主要酶的抑制作用及其机理初探

 【目的】分析柿子单宁（persimmon tannin，PT）对江浙蝮蛇、尖吻蝮蛇、眼镜蛇毒中主要酶活力的抑制作用，初步研究两者相互作用的机理。【方法】将蛇毒与PT以不同比例混合后在37℃下温育1 h，离心分离，测定上清液中主要酶活力变化，并采用SDS-聚丙烯酰胺凝胶电泳对粗毒和作用后所得沉淀及上清液进行分析。【结果】当蛇毒与PT质量比达到1﹕1时，粗毒中蛋白质水解酶、磷脂酶A2、L-氨基酸氧化酶、精氨酸酯酶、乙酰胆碱酯酶、类凝血酶活力被完全抑制，且酶活力的下降与PT含量呈剂量增加效应；SDS-聚丙烯酰胺电泳表明，PT与蛇毒蛋白具有很强的非特异性结合能力。但对不同结构蛋白质结合能力和选择性也明显不同。【结论】柿子单宁在体外条件下对蛇毒中几种酶的活力具有明显的抑制作用，PT与蛋白结合是导致酶失活的重要原因。

Study on Inhibitory Effects of Persimmon Tannins on Activities of Major Enzymes from Several Snake Venoms and Its Mechanism

【Objective】To study the inhibitory effects of persimmon tannins (PT) on the activities of proteolytic enzyme, phospholipase A2, L-amino acid oxidase, arginine esterase, acetylcholinesterase and thrombin-like enzyme from Agkistrodon halys Pallas, Agkistrodon acutus, Naja naja atra venom , and the action mechanism between venom and PT. 【Method】 Different amounts of PT were mixed with snake venoms, after incubation at 37℃ for 1h and centrifuge, the enzyme activities of proteolytic enzyme, phospholipase A2, L-amino acid oxidase, arginine esterase, acetylcholinesterase and thrombin-like enzyme from the supernatants were mensurated, and the precipitates , supernatants and venom were analyzed by SDS-PAGE.【Result】The enzyme activities of proteolytic enzyme, phospholipase A2, L-amino acid oxidase, arginine esterase, acetylcholinesterase, and thrombin like enzyme were inhibited completely when the rate of snake venom and PT reached 1:1 (w/w), and the inhibitory effect was in a dose-dependent manner; PT was found to have very high combinative ability with venom proteins in a non-specifically manner.，but with different selectivity for different protein.【Conclusion】It was suggested that the enzyme activities from snake venoms could be inhibited remarkably by persimmon tannin in vitro by non-specifically combination.