Review Material II

• Chapter 9: Early protein chemistry studies were almost all done using hemoglobin. Hemoglobin is a terameric protein that transports oxygen.

myogobin consists of 8 alpha helices and is a protein that stores oxygen.
different binding affinities of oxygen for hemoglobin and myoglobin
Cooperative binding and models of binding (symmetry and sequential)
Role of BPG
Hill equation
Bohr effect

• Chapter 12:

enzyme catalyzed reactions
cofactors and coenzymes
catalyst: lower activation energy
enzyme terms (substrate, holoenzyme, apoenzyme, zymogen, proenzyme, pre-enzyme, cofactor and coenzyme)
active site
regulation of enzyme activity- different levels including enzyme availability, conformational and structural alterations
Classification of enzymes organization into six different mechanistic groups.
Oxidoreductase: oxidation/reduction enzymes, example: alcohol dehydrogenase
Transferase: transfer intact group from donor to acceptor, example: aspartate aminotransferase
Hydrolase: hydrolytic cleavage, example: chymotrypsin
Lyase: addition or subtraction from a double bond, example: carbonic anhydrase
Isomerase: racemization, epimerization, cis-trans isomerization, example: phosphoribuloepimerase
Ligase: condensation of two molecules linked to the breaking of pyrophosphate bond, example: pyruvate carboxylase
 
• Chapter 13: Enzyme kinetics follow principles of chemical kinetics

velocity increases linearly with increasing enzyme concentration
velocity increases in hyperbolic manner with increasing substrate concentration
enzyme reaction goes through ES complex
Michaelis derivation verses Briggs Haldane
Lineweaver-Burk Plot: 1/v vs 1/S
inhibition patterns
Competitive inhibition: inhibitor competes directly with substrate
alters apparent Km (increase) not Vmax
Non-competitive inhibition: inhibitor binds both enzyme and ES complex
alters apparent Vmax (lower) not Km
Uncompetitive inhibitor binds directly to ES complex
alters apparent Km and Vmax
allosteric effector (concerted mechanism, sequential mechanism, activator or inhibitor) Cleland nomenclature
calculation and understanding of kinetic constants including Km, Vmax, Ki and enzyme efficiency kcat/Km

Problem set for chapters 9, 12 13

Back to Biochem I tentative schedule

Contact: Stapleton@wmich.edu

URL- http://www.wmich.edu/pathname/filename.html (if known, otherwise omit) Revised Date: June 24, 1997