Lecture12-Ch6-Oct3_2007

Lecture12-Ch6-Oct3_2007 - 6 Hexokinase...

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Enzymes are affected by pH. Here are 2 examples:
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Transition state analogs = inhibitors that resemble the transition state of the reaction
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Major tricks:  Forms acyl-enzyme covalent intermediate General acid-base catalysis Use of binding energy to stabilize transition state intermediates (the oxyanion hole)
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Substrate binds     = peptide
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2 But the pKa of a Ser side chain is >13.  How can Ser act as a  nucleophile? oxyanion hole
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(acylation) 3 = amino-terminal part of peptide
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4
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5 (deacylation)
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Unformatted text preview: 6 Hexokinase ===>example of an induced fit mechanism substrate = glucose, Mg-ATP Enolase ==> example of general acid-base catalysis & metal ion catalysis Regulation by feedback inhibition What if our plot of reaction rate vs. [substrate] was sigmoidal? (not hyperbolic!) What does this tell us about the enzyme? Examples of regulation by post-translation modifications of proteins Activation of chymotrypsin & trypsin by proteolysis...
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This note was uploaded on 12/02/2009 for the course CH 53890 taught by Professor Raymonds during the Spring '09 term at University of Texas at Austin.

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Lecture12-Ch6-Oct3_2007 - 6 Hexokinase...

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