生物化學(xué)資料：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,無乳糖分解酶或乳糖分解酶活性低下的E-coli在含乳糖的培養(yǎng)基中培養(yǎng)一段時(shí)間后，細(xì)菌體內(nèi)涉及乳糖分解的有關(guān)酶類活性明顯增加，其機(jī)制是乳糖對(duì)乳糖操縱子的,別構(gòu)激活作用 共價(jià)修飾作用 正反饋?zhàn)饔?誘導(dǎo)作用 阻遏作用,D,Question 2,關(guān)于反競(jìng)爭(zhēng)抑制作用的敘述，正確的是,抑制劑既與酶相結(jié)合又與ES復(fù)合物相結(jié)合 抑制劑只與ES復(fù)合物相結(jié)合 抑制劑使Km降低，Vmax升高 抑制劑使Km升高，Vmax降低 抑制劑不改