铜绿金龟子幼虫酚氧化酶特性初探
Enzymatic properties of phenoloxidase from Anomala corpulenta Larvae
酚氧化酶（EC.1.14.18.1，PO）是结构复杂的多亚基的含铜氧化还原酶，它在昆虫的变态发育和免疫系统中起着重要作用。本文以铜绿金龟子幼虫酚氧化酶为研究对象，以L-多巴为底物研究了该酶的基本酶学特性。结果表明：该酚氧化酶的最适温度为50℃，最适pH值为7.5，以L-多巴和邻苯二酚为底物时，铜绿金龟子幼虫酚氧化酶的Km分别为11.11 mmol/L和9.52mmol/L，Vm分别为107.53 U/mg和41.67 U/mg。研究了桑黄素对铜绿金龟子幼虫酚氧化酶活力的抑制作用，结果表明，以L-多巴为底物时，桑黄素可以明显抑制该酚氧化酶的活性，其IC50为1.05 mmol/L，同时，研究表明桑黄素为铜绿金龟子幼虫酚氧化酶的可逆性、竞争性抑制剂，其抑制常数（KI）为0.54 mmol/L。
he kinetic parameters of partially purified phenoloxidase (PO, EC. 1.14.18.1) from the larvae of Anomala corpulenta M. were determined, using L-3, 4-dihydroxyphenylalanine (L-DOPA) as substrate. The optimal pH and temperature of the enzyme for the oxidation of L-DOPA were determined to be at pH 7.5 and at 50 C, respectively. At pH 7.5 and 50 C, the Michaelis constant (Km) and maximal velocity (Vm) of the enzyme for the oxidation of L-DOPA were determined to be 11.11 mmol/L and 107.53 U/mg, respectively, and the Km and Vm of PO for the oxidation of catechol were 9.52 mmol/L and 41.67 U/mg, respectively. Morin could effectively inhibit the activity of phenoloxidase and this inhibition was reversible and competitive, with the IC50 of 1.05 mmol/L. The inhibition constants were estimated to be 0.54 mmol/L.
李滨、崔晶晶、薛超彬、刘伟
生物化学昆虫学
酚氧化酶桑黄素抑制机理铜绿金龟子
nomala corpulenta Phenoloxidase Morin inhibitory mechanism
李滨,崔晶晶,薛超彬,刘伟.铜绿金龟子幼虫酚氧化酶特性初探[EB/OL].(2013-12-20)[2025-08-18].http://www.paper.edu.cn/releasepaper/content/201312-600.点此复制
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