Caspases与细胞凋亡

Caspases是一类蛋白裂解酶,在细胞内以无活性的酶原形式存在。Caspases具有半胱氨酸激活位点和底物裂解位点,当作用于胞内特异性底物后将引起细胞凋亡。Caspases的底物特异性由其裂解位点N-端的4个氨基酸残基决定,其底物裂解部位通常位于靶蛋白质一级结构中Asp残基后,数目由一个到多个不等。Caspase酶系作为细胞凋亡的中枢效应器,在细胞凋亡的启动及进程中发挥着极为重要的作用。无活性的caspases酶原主要通过上游caspseses加工机制、邻近诱导机制或偶联调节亚基机制三种方式被激活而引发细胞凋亡。细胞凋亡是细胞生命活动的基本特征之一。本文就引起凋亡的酶系和细胞凋亡的生化机理加以综述。

Caspases and Apoptosis

Caspases are a kind of proteases, which are in form of zymogens in cells and have Cys activating site and substrate lysing site. It will result in apoptosis when caspases lyse their special substrates in cells. Four amino acid residues of N terminal of lysing site determine the substrate specificity of caspsaes. The substrate lysing site from one to several of caspases usually lies behind Asp residue in the primary structure of target proteins. As central effetors of apoptosis, caspases bring important function into play in the start ups and courses of apoptosis. Activation of caspase zymogens depends on processing by an upstream caspase, induced proximity or association with a regulatory subunit, which can induce happening of apoptosis. Apoptosis is the essential character for cells. This review summarizes the enzymes and biochemical mechanisms about apoptosis.