生物化学资料：酶活性

1、Regulation of Enzyme Activity,A question,What do you think are factors affecting enzyme activity,Overview,Inhibition by enzyme inhibitors,Regulation of allosteric enzyme,Covalent modification,Induction and repression of enzyme synthesis,1,Inhibition by enzyme inhibitors,Comparison Table,Effect on th

2、e Lineweaver-Bruk plot,Competitive inhibitor,Noncompetitive inhibitor,Pravastain competes with HMGCoA for the activity site,Example,Anti-competitive inhibition,Enzyme inhibitor only binds to ES, and they are not in combination with free enzyme,Feature,Both and are decrease,Lineweaver-Bruk plot,Regul

3、ation of allosteric enzyme,Allosteric enzyne are regulated by molecules called effectors,Binding site,Not active site,Binding mode,Noncovalently,Mode Figure,Classification of effectors,Effectors,Homotropic effectors,1、The substrate itself serves as an effector,Feature,2、Most often, an allosteric sub

4、strate functions as a positive effector,Heterotropic effectors,The effector may be different from the substrate,Example,Feedback inhibition,Both of these two effectors could affect or,Covalent modification,Protein phosphorylation is the main form of covalent modification,Its also one of the primary

5、ways in which cellular processes are regulated,Sites：Ser-OH、Thr-OH、Tyr-OH,Reversible covalent modification,Process of covalent modification,Example,Other covalent modification,Zymogen,A precursor in the inactive state of the enzyme is called Zymogen,As a storage form of the enzyme,The regulation of enzyme synthesis,Induction,Repression,Question 1,无乳糖分解酶或乳糖分解酶活性低下的E-coli在含乳糖的培养基中培养一段时间后，细菌体内涉及乳糖分解的有关酶类活性明显增加，其机制是乳糖对乳糖操纵子的,别构激活作用 共价修饰作用 正反馈作用 诱导作用 阻遏作用,D,Question 2,关于反竞争抑制作用的叙述，正确的是,抑制剂既与酶相结合又与ES复合物相结合 抑制剂只与ES复合物相结合 抑制剂使Km降低，Vmax升高 抑制剂使Km升高，Vmax降低 抑制剂不改