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44 Cards in this Set
- Front
- Back
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2,3 BPG
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- heterotropic allosteric modulation of oxygen binding
- BPG binds at distant site and regulates affinity by conformation change - reduces affinity for O2 - increased at high altitudes - stabilizes tense state, more O2 released |
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At sea level, O2 delivered to the tissues is what percent of the max that could be carried by the blood?
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38%
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At high altitudes, where pO2 is low, the delivery of O2 to tissues is what percent?
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30%
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At high altitudes, when 2,3BPG increases, the delivery of O2 to tissues is what percent?
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37%, less affinity, releases more O2 to tissues
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IgG
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- 2 antigen binding sites
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ELISA
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1.) coat surface w/ antigen
2.) block surface w/ nonspecific antigen 3.) primary antibody against specific antigen 4.) antibody-enzyme complex binds primary antibody 5.) colored product forms when substrate added |
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actin myosin
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- interaction breakdown ATP to move
- convert one form of energy to another |
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delta G, standard free energy change
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- overall standard free-energy change in the direction S->P
- stays the same |
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activation energy
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the difference between energy levels of the ground state and the transition state
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rate-limiting step
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- determines the overall rate
- has the highest activation energy |
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Keq =
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= [P]/[S]
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The bigger Keq, what happens to delta G?
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delta G decreases and more product is being formed
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Where does the source of energy come from to lower activation energy?
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rearrangements of covalent bonds and noncovalent interactions between enzyme and substrate
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The enzyme must be complementary to what in order to catalyze reaction?
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to the transition state
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delta Gm
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difference between transistion state energies of uncatalyzed and catalyzed reactions
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delta Gb
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- binding energy
- the energy from the binding of substrate to enzyme - used to lower activation energies, it equals the amount by which transition state is lowered |
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specific acid-base catalysis
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uses H+ and OH- ions from water, nonenzymatic
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general acid-base catalysis
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proton transfer by AA side chains, nonenzymatic
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When proton transfer is faster than the breakdown of intermediates, what will help the rate of reaction?
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none, other acid or base will not increase rate of reaction
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When proton transfer is slower than the breakdown of intermediates, what will hlep the reate of reaction?
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alternative acids or base will increase rate of reaction
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Reaction catalyzed by chymotrypsim
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General base catalysis and covalent catalysis, then specific
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covalent catalysis
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a transient covalent bond is formed between enzyme and substrate
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metal ion catalysis
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ionic interactions between enzyme-bound metl and a substrate can help stabilize charged reaction transition state
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Km
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the substrate concentration at which rate is 1/2Vmax
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If Km decrease, what does it mean for substrate concentration?
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it needs less substrate to reach 1/2Vmax
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If Km increases, what does it mean for substrate concentration?
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it need more substrate to reach 1/2Vmax
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Michaelis-Menten equation
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Vo = Vmax[S]/Km + [S]
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Km =
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= (k2+k-1)/k1
- breakdown/form |
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Kcat
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rate constant for rate limiting step
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to compare enzymes
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- Kcat/Km
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Lineweaver-Burke Equation
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1/Vo = Km/Vmax[S] + 1/Vmax
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y-int is
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1/Vmax
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x-int is
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-1/Km
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slope is
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Km/Vmax
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Random bisubstrate reaction
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random binding to make ternary complex
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Ordered bisubstrate reaction
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substrate 1 binds first, then substrate 2 binds
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Ping-pong bisubstrate reaction
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no ternary complex, release first product then bind to 2nd substrate
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double reciprocal plot w/ intersecting lines as substrate 2 is increasing
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random w/ ternary complex
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double reciprocal plot w/ parallel lines as substrate 2 increases
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ping-pong, no ternary complex
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double reciprocal plot w/ change in Km and Vmax doesn't change, intersecting lines
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Competitive inhibition
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plot w/ Vmax changed and Km changed, parallel lines
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Uncompetitive inhibition
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plot w/ Vmax and Km change, intersecting lines
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Mixed inhibition
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binding of positive modulator
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- makes affinity for [S] greater
- decrease K0.5 |
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binding of negative modulator
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- makes affinity for [S] smaller
- increase K0.5 |
