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Unformatted text preview: Bio Lec #2 09/02/08 NB--- Catalysts lower the activation energy of a reaction by stabilizing the transition state.------ Catalysts do not change G------ Catalysts are not consumed in the reaction ENZYMES-Protein catalysts that speed up and control biological reactions- Typically catalyze only one reaction- Most biological chemical reactions occur only in the presence of enzymes---Speed up reaction rates by millions of times---- Carbonic anhydrase catalyzes I million reactions/second HOW DO ENZYMES WORK?--------Enzymes bring substrates together in specific positions that facilitate reactions--------Enzymes are very specific as to which reactions they catalyze --------Substrates bind to the enzymes active site--------Interactions between the enzyme and the substrate >> Stabilizes the transition state >> Decrease the activation energy LOOK AT FIG 3-22 ENZYME ACTIVE SITES-Enzyme active site R- groups interact with the substrate through:--- Hydrogen Bonding--- Temporary covalent bonding during transfer of atoms--- Proton transfer aided by acidic or basic R-Groups- The resulting reaction Products----- Have a lower affinity for the active site---- Are the released by the active site 1) IN ITIATION-Reactants bind to the active site in a specific orientation...
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