Ch. 9 - 3 unit Cabonic anhydrase contains a Zn +2 ion at...

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Bining energy released Catalytic Strategies Selectively cleaves peptide bonds on COO- side of large hydrophobic AAs such as Trp, Tyr, Phe, and Met Generate a nucleophile that can attack a substrate. Employs a powerful nucleophile to attack the unreactive carbonyl carbon atom of the S It have a hydroxy group that is why it is so reactive Catalytic triad: OH- group generates an alkoxide, a powerful nucleophile. Peptide hydrolysis Carbonic anhyydrase is a metalloenxzyme E contains highly reactive Ser residue Use covalent catalysis Chymotrypsin Catalytic S. .. Audio recording started: 11:19 AM Wednesday, October 13, 2010 Covalent bond Ch. 9 11:17 AM Lecture Page 1
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The Zn+2 is boind by 3 His imidazoles and 1 water (overall cahrge of the Zn(His)
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Unformatted text preview: 3 unit Cabonic anhydrase contains a Zn +2 ion at the bottom of a = 15A deep active site cleft which is essential for enzymatic activity When the acid is deprotonated (high pH form) the enzyme is active When the acid is protonated (low pH form( the enzyme. . Zinc facilitates the release of a proton from a water molecule CO2 binds to the enzyme active site, positioned to react with hydroxide ion The hydroxide ion attacks CO2 forming bicarbonate ion Catalytic site is regenerated by release of bicarbonate and binding of another water. A plot of pH vs. catalytic activity (k cat) CARBONIC ANYDRASE IMPLICATES AN ACID WITH PKA+ 7 in the catalytic mechaism Zinc activation of water Lecture Page 2...
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This note was uploaded on 05/30/2011 for the course BIOCHEMIST 4033 taught by Professor Dorristerry during the Fall '10 term at Florida A&M.

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Ch. 9 - 3 unit Cabonic anhydrase contains a Zn +2 ion at...

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