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Part II . Protein Dynamics. Chapter 14 Enzyme Kinetics. 14.1 Enzymes are Biological Catalyst. 1878 ------------ enzyme 1913 ------------ Michailis-Menten equation 1926 ------------ urease 1982 ------------ ribozyme 1986 ------------ abzyme.
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Part II . Protein Dynamics
Chapter 14 Enzyme Kinetics
14.1 Enzymes are Biological Catalyst 1878 ------------ enzyme 1913 ------------ Michailis-Menten equation 1926 ------------ urease 1982 ------------ ribozyme 1986 ------------ abzyme
Nearly all enzymes are proteins, although a few catalytically active RNA molecules have been identified. Enzyme are catalysts that increase the rate of a chemical reaction without being changed themselves in the process.
enormous catalytic power 8 20 10 ----10 • specificity substrate • regulation
Holoenzyme = apoenzyme + cofactor Coenzyme Prosthetic group • Monomeric enzyme • Oligomeric enzyme • Multienzyme system
14.2 Enzyme Classification and Nomenclature Oxidoreductases Transferases Hydrolases Lyases Isomerases Ligases
ATP:D-glucose-6-phosphotransferase hexokinase enzyme commision E.C.2.7.1.2 class Individual entry subclass sub-subclass
14.3.1 The Michaelis-Menten Equation Enzyme-substrate complex k1 k3 k2 E + S ES E + P
Michaelis-Menten Equation Vmax[S] v = ------------- Km + [S] • Constant Km V = Vmax / 2 , Km = [S]
14.3.3 Effect of Temperature on Enzymatic Activity Optimum temperature
14.4 Enzyme Inhibition Any molecule which acts directly on an enzyme to lower its catalytic rate is called an inhibitor.
14.4.1 Irreversible Inhibition Covalent bond
14.4.2 Reversible Inhibition • competitive inhibition
14.5 Enzyme Activity • Reactive velocity • Active unit (U) • Specific activity • U/mg protein • Turnover Number (kcat )
14.6 RNA and Antibody Molecules as Enzymes 14.6.1 Catalytic RNA Molecules: Ribozymes