8 10.5 Catalytic reactions Catalyzed reactions Out-class extensive reading Levine, p.577 1717 Enzyme catalysis
§10.5 Catalytic reactions Catalyzed reactions Out-class extensive reading: Levine, p.577 17.17 Enzyme catalysis
10.5 Catalytic reactions 5.6 Enzyme catalysis (1) Enzymes Enzymes are biologically developed catalysts Enzymes are proteins, ranging in molecular weight from about 6000 to several million about 150 kinds have been isolated in crystalline form The diameter of enzyme usually ranges between 10 100 nm. Therefore, the enzyme catalysis borders the homogeneous catalysis and the heterogeneous catalysis Structure of nitrogenase
5.6 Enzyme catalysis Enzymes are biologically developed catalysts. Enzymes are proteins, ranging in molecular weight from about 6000 to several million. About 150 kinds have been isolated in crystalline form. The diameter of enzyme usually ranges between 10 ~ 100 nm. Therefore, the enzyme catalysis borders the homogeneous catalysis and the heterogeneous catalysis. 10.5 Catalytic reactions Structure of nitrogenase （1）Enzymes
10.5 Catalytic reactions 5.6 Enzyme catalysis (1) Enzymes Luciferase(荧光素酶) is a generic name for enzymes commonly used in nature for bioluminescence http:/en.wikipediaorg/wiki/imageLuciferase-1ba3.png
http://en.wikipedia.org/wiki/Image:Luciferase-1BA3.png Luciferase (荧光素酶) is a generic name for enzymes commonly used in nature for bioluminescence. 5.6 Enzyme catalysis 10.5 Catalytic reactions （1）Enzymes
10.5 Catalytic reactions 5.6 Enzyme catalysis (1) Enzymes: Cy H Figure 1. View of the M centre in the MoFe protein of A. vinelandii nitrogenase from X-ray crystallographic data of Rees et al. as first reported in199212
5.6 Enzyme catalysis 10.5 Catalytic reactions （1）Enzymes:
10.5 Catalytic reactions 5.6 Enzyme catalysis Light harvesting protein Central chlorophyll Reaction center Oxygenevolving center of reaction center Chlorophy‖ Chlorophyll(叶绿素) Plastoquinone B(质体醌 Tyrosine(络氨酸) Light harvesting protein
Central chlorophyll of reaction center Light harvesting protein Reaction center Light harvesting protein 5.6 Enzyme catalysis 10.5 Catalytic reactions Chlorophyll (叶绿素) Plastoquinone B （质体醌） Tyrosine (络氨酸)
10.5 Catalytic reactions 5.6 Enzyme catalysis Oxygen-evolving center Water yrosine Chlorophyll O xygen evolving center Photosystem I cofactors
Oxygen evolving center Photosystem I cofactors 5.6 Enzyme catalysis 10.5 Catalytic reactions
10.5 Catalytic reactions 5.6 Enzyme catalysis Important hydrolytic enzymes (2) Kinds of enzymes: pepsin Hydrolysis of proteins 1) hydrolytic enzymes diastase Hydrolysis of starch 2)oxidation-reduction enzymes urease hydrolysis of urea 3)Dehydration invertase hydrolysis of sucrose Zymase hydrolysis of glucose Deoxygenation maltase Hydrolysis of maltose 5)Esterification oxidation-reduction enzymes 6)Condensation SOD Decomposition of etc (Superoxide Dismutase)superoxide(02) Nitrogenase Dinitrogen fixation
（2）Kinds of enzymes: 1) hydrolytic enzymes 2) oxidation-reduction enzymes 3) Dehydration 4) Deoxygenation: 5) Esterification: 6) Condensation etc. 5.6 Enzyme catalysis 10.5 Catalytic reactions pepsin Hydrolysis of proteins diastase Hydrolysis of starch urease hydrolysis of urea invertase hydrolysis of sucrose zymase hydrolysis of glucose maltase Hydrolysis of maltose Important hydrolytic enzymes oxidation-reduction enzymes SOD (Superoxide Dismutase) Decomposition of superoxide (O2 - ) Nitrogenase Dinitrogen fixation
10.5 Catalytic reactions 5.6 Enzyme catalysis 1913. the German chemist Leonor Michaelis and (3) Kinetics of enzyme catalysis Dr. Maud Leonora Menten repeated Henri's experiments and confirmed his equation, which y referre Mich Menten kinetics (So ometimes also Henri 1902 Victor Henri proposed a ae y Michaelis-Menten kinetics) quantitative theory of enzyme kinetics In 1925.G. E. Briggs and B. S. Haldane derived kinetic 1909. Peter Lauritz Sorensen that are still wide defined the logarithmic pH considered today a starting scale and introduced the N point in modeling enzymatic concept of buffering activity
1902 Victor Henri proposed a quantitative theory of enzyme kinetics 5.6 Enzyme catalysis 10.5 Catalytic reactions 1913, the German chemist Leonor Michaelis and Dr. Maud Leonora Menten repeated Henri's experiments and confirmed his equation, which is now generally referred to as MichaelisMenten kinetics (sometimes also HenriMichaelis-Menten kinetics). 1909, Peter Lauritz Sørensen defined the logarithmic pHscale and introduced the concept of buffering. In 1925, G. E. Briggs and J. B. S. Haldane derived kinetic equations that are still widely considered today a starting point in modeling enzymatic activity. (3) Kinetics of enzyme catalysis
10.5 Catalytic reactions 5.6 Enzyme catalysis (3) Kinetics of enzyme catalysis Dependence of rate on the substrate concentration of hydrolysis of adenosine 1.0x10-5 triphosphate (ATP)with myosin as a 8.0x10-6 catalyst 60x10 reaction rate∝[E] 4.010-6 dependence on [s] is compl 2.0×106 K[E]o[S] m=kIEl 0.00010.0020.004 0060.0080.010
(3) Kinetics of enzyme catalysis Dependence of rate on the substrate concentration of hydrolysis of adenosine triphosphate (ATP) with myosin as a catalyst . reaction rate [E] the dependence on [S] is complex. 3 0 [E] m r k = 0 r k = [E] [S] 5.6 Enzyme catalysis 10.5 Catalytic reactions
10.5 Catalytic reactions 5.6 Enzyme catalysis (3)Kinetics of enzyme catalysis MAUD LEONORA MENTEN 1879-1960 Leonor michaelis Maud Leonora menten Michaelis L, and Menten mL Kinetik der Invertinwirkung Biochem. Z. 1913: 49: 333-369 https:/en.wikipediaorg/wiki/leonor_michaelIs
Michaelis L. and Menten M.L. Kinetik der Invertinwirkung Biochem. Z. 1913; 49:333–369 Leonor Michaelis https://en.wikipedia.org/wiki/Leonor_Michaelis Maud Leonora Menten 5.6 Enzyme catalysis 10.5 Catalytic reactions (3) Kinetics of enzyme catalysis