Enzyme substrate binding for example in the rnase

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Unformatted text preview: (selective),oracceptonesubstrate,makeoneproductfromit,twopossibilities, ifenzyme:singleroduct,specificproduct.Canbeboth Specificity exhibited in: 1. enzymesubstratebinding Enzyme-substrate binding 2. reactioninitiationinitiation Reaction 3. particularreactionreaction steps Particular steps 4. transitionstatestabilization stabilization Transition state Allows cell to control the rates of individual reactions without affecting others. RNase: specificity (Most) Enzymes are highly selective catalysts 1. Enzyme-substrate binding For example in the RNase mechanism: The pyrimidine binding pocket is geometrically/chemically complementary to pyrimidine bases but not purine bases. alwayscleavephosphodiesterlinkageafterpyrimidine Binding positions the phosphodiester linkage of the substrate near the active site reactive residues, so only a phosphodiester linkage 3’ to a pyrimidine base is hydrolyzed. RNase: specificity (Most) Enzymes are highly selective catalysts 2. Reaction initiation For example in the RNase mechanism: RNase binds ssDNA, but does not catalyze its hydrolysis. 2'hydroxylisthenucleophile,DNAdoesnothave2'hydroxyl His-1...
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This note was uploaded on 04/01/2014 for the course BIOL 201 taught by Professor Chowrira during the Winter '13 term at The University of British Columbia.

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