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11 Cards in this Set
- Front
- Back
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enzymes
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biological catalysts (only affect rate, not thermodynamics -- Keq and G)
-generally proteins |
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prosthetic groups
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cofactors (inorganic)
coenzymes (organic) |
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enzyme facts
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-only need a little
-altered during a reaction but reversible (can be used again and again) -work at T/pH of cell (98.6 and 7) -very specific -- only bind certain substrates |
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transition state
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-molecule changes shape to break a bond during a chemical rxn (geometry/electron distribution change)
-transition state is at Ae |
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enzymes lower
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activation energy.
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bind substrates at
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active site. may induce a conformation that is a better fit.
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E-S complex
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noncovalent interaction.
-raises reactivity of substrate: orientation, molecular change by donating/taking protons, and deforms molecule (forcing into transition state) |
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enzyme kinetics
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-max rate (at which an enzyme can catalyze a rxn) -- when there are more substrate molecules than enzyme.
-at Vmax/2 --- Km (michaelis constant). the smaller, the more affinity the enzyme has for the substrate (Km on x-axis corresponds to higher slope -- quicker rxn). |
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inhibition
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irreversible -- bind tightly to enzyme and destroy activity
reversible -- can be removed (inhibit for a time) |
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types of reversible inhibitors
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competitive -- compete for active site. if enough substrate, can completely overcome inhibitor presence.
noncompetitive --bind to "allosteric" site not the active site and change protein shape so it can't bind protein |
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enzyme regulation
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control metabolism by controlling concentration of enzyme, and by changing active site.
covalent -- add/remove phosphate group allosteric -- binds to allosteric site -- inhibitory or stimulatory (changes active site) |
