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10 Cards in this Set
- Front
- Back
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What are the features of Km |
1)constant derived from other constants 2) Km is under true M-M conditions and is an estimate of the dissociation constant of E from S (measure of affinity) 3) Small km = tight binding (high affinity) |
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How is a lineweaver burk plot made, what are the x/y intercepts |
take the reciprocal of both sides of the M-M eqn, plot 1/v vs 1/[s] X-intercept: - 1/km Y-intercept: 1/Vmax |
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What is the turnover number |
Kcat the number of substrate molecules converted to product per enzyme molecule per unit of time, when E is saturated w/ S Kcat = K2 under saturated conditions |
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What is reversible inhibition |
Competitive: Inhibitor binds to enzyme only (increases Km) Non-Competitive: Inhibitor can bind to E and ES (decreases Vmax) |
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What type of inhibition causes increased Km |
reversible competitive inhibition |
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What type of inhibition causes decreased Vmax |
reversible NON-competitive inhibition |
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What kind of inhibition can you not fix with increased [S] |
non-competitive b/c it binds to an allosteric site |
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Explain Asprin and Irreversible enzyme inhibition |
ASA irreversibly modifies COX acetyl group transfered to a serine residue in the channel leading to active site (acetylated COX) Covalent modification is irrevisible |
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Explain the mechanism of penicillin |
Penicilin covalently reacts w/ essential serine in active site of glycopeptide transpeptidase |
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If the M-M model fits, what is Kcat equal to |
Kcat = K2 = Vmax/Et |
