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17 Cards in this Set
- Front
- Back
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R + H -> (K1) <- (K2) RH
Rate constant formation Rate constant dissociation Kd |
K1 - rate constant formation
K2 - rate constant dissociation Kd = K2/K1 |
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Myoglobin vs hemoglobin
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Myoglobin - 1 O2 binding site (B-chain)
Hemoglobin - 4 O2 binding site (2 alpha, 2 beta polypeptide chain). Cooperative binding myoglobin - cardiac and skeletal muscle and picks up oxygen relased by hemoglobin Both have same Heme group |
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Heme in oxygen binding of hemoglobin
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His bind to Fe2+ on one side of the prphyrin ring. O2 binds to Fe2+ on the other side. O2 causes conformation change that pulls Fe2+ back into the plane of the ring As proximal His moves it move the helix that contains it.
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sickle cell anemia
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A val is substituted for glu on a beta chain2
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Km
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michaelis constant and is a measure of the apparent affinity of the enzyme for its substrate
tells you how efficient an enzyme is. How efficiently it can identify substrate. Lower - MORE EFFICIENT |
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Ligand binding and Michaelis-Menten equation
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They have the same equation:
B = Vo Bmax = Vmax [H] = [S] Kd = Km Kd = k2/k1 , Km = (k2 + k3)/K1 |
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Kd and Km
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R + H -> (k1) <- (k2) RH
Kd = k2/k1 E+S -> (K1) <- (K2) ES Km = K2/k1 = Kd E+S -> (k1) <- (k2) ES -> (K3) E+ P Km = ( K2 + k3) / K1 |
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Anion
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A negatively charged ion, especially the ion that migrates to an anode in electrolysis.
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Cation
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An ion or group of ions having a positive charge and characteristically moving toward the negative electrode in electrolysis.
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Vmax
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fastest rate at which an enzyme catalyzed reaction will undergo.
Saturation kinetics. Once the substrate concentration exceeds the enzyme concentration the enzymes are said to be saturated since EVERY enzyme is substrate bound. |
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Significance of hyperbolic nature of Michaelis-Menten curve
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-initially there are more enzymes to bound substrate so its very fast (steep slope)
-as more enzymes are bound the reactions slows - when enzymes are fully saturated by the substrate the reaction has reached Vmax |
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isozymes
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enzymes that catalyze the same reaction but have different primary or quaternary structures
- allow fine-tuning of metabolism to meet needs of a given tissue |
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hexokinase vs. Glucokinase
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Hexokinase (brain) has low Km for glucose - it is more efficent bc it relies soley on glucose.
glucokinase - liver- has other energy sources and doesn't need to be as efficient |
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Reversible inhibition vs. Irreversible inhibition
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reversible ( temporary)
-competitive -noncompetitive irreversible (permanent) |
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noncompetitive inhibitor
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binding of noncompetitive inhibitor causes change in enzyme conformation which blocks access to active site
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competitive inhibitor
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inhibitor binds directly to active site which blocks access of substrate to active site
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irreversible inhibitor
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binds and destroy a function groups on an enzyme that is essential for enzyme activity - COVALENT
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