Enzymes commonly employ one or more of the following strategies to catalyze specific reactions: 1.Covalent Catalysis共价催化：the active site contains a reactive group,usually a powerful nucleophile,that becomes temporarily covalently attached to a part of the substrate in the course of catalysis.The proteolytic enzyme provides an excellent example of this strategy 共价催化的活性位点有活泼基团，通常是很强的亲核基团。 在酶促过程中亲核基团能暂时性共价连接底物。 2.General Acid-Base Catalysis酸碱催化.In general acid- base catalysis,a molecule other than water plays the role of a proton donor or acceptor. 酸碱催化中，水分子之外的物质提供质子或接受质子1. Covalent Catalysis共价催化: the active site contains a reactive group, usually a powerful nucleophile, that becomes temporarily covalently attached to a part of the substrate in the course of catalysis. The proteolytic enzyme provides an excellent example of this strategy . 共价催化的活性位点有活泼基团，通常是很强的亲核基团。 在酶促过程中亲核基团能暂时性共价连接底物。 2. General Acid–Base Catalysis酸碱催化. In general acid– base catalysis, a molecule other than water plays the role of a proton donor or acceptor. 酸碱催化中，水分子之外的物质提供质子或接受质子 Enzymes commonly employ one or more of the following strategies to catalyze specific reactions: