ch369_sum10_enz_3_notes

ch369_sum10_enz_3_notes - Plan for today is to continue...

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Plan for today is to continue with chapter 7. “Enzyme kinetics & enzyme inhibition”
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Last time - Michaelis-Menten enzyme kinetics: [S] = initial substrate concentration, typically in units of moles/liter. v o = initial reaction velocity (such as moles of product produced / sec)
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K M is the substrate concentration when the initial reaction velocity is one-half of its maximum value. Three numbers that can describe an enzyme’s catalytic abilities are: K M and V max and k cat initial reaction velocity V 0 [S]
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K M is a measure of how tightly an enzyme binds substrate. High K M indicates weak substrate binding. Lower K M means tighter substrate binding.
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Another quantity used to characterize enzymes is k cat . k cat = V max / [E] total k cat is called “catalytic constant” or “turnover number”. k cat = number of catalytic cycles by each active site per second. Enzyme k cat Staph. nuclease 95 sec -1 Chymotrypsin 190 sec -1 Trios phosphate isomerase 4300 sec -1 Carbonic anhydrase 1,000,000 sec -1
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Finding V max and K M : May use a “ Lineweaver-Burk plot
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Sigmoidal rate vs [S] curve is typical of cooperative substrate binding. Such a curve is not described by simple M-M kinetics. Not all enzymes follow Michaelis-Menten kinetics.
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1. Regulation by enzyme inhibitors. a) Irreversible inhibitors.
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This note was uploaded on 08/26/2010 for the course CH 369 taught by Professor Kbrowning during the Spring '07 term at University of Texas at Austin.

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ch369_sum10_enz_3_notes - Plan for today is to continue...

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