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24 Cards in this Set
- Front
- Back
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turnover number
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number of substrate molecules converted to product. per enzyme molecule per second
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apoenzymes
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protein component only
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holoenzymes
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contain proptein component and cofactors
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isozymes
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different enzymes that catalyze the same rxn
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protozymes
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aka zymogens. inactive enzymes that have to have portions cleaved to become active.
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Energy barrier
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free energy of activation(enzymes lower this)
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chymotrypsin
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hydrolyzes penptide bond on c side of phe, tyr, trp
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catalytic triad
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SDH- Serine aspartate histidine
stratedgy of proxomity and orientation |
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functional vitamin deficiency
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inhibition of coenzyme synthesis or failure in transport mechanism
Opposed to dietary vit deficiency which is just inadequate intake. Example(transport failure):Vitamin B12 deficiency due to failure of intracellular transport of B12 by transcobalamin-2 |
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activation-transfer coenzymes
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bond covalently with substrate.
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oxidation-reduction coenzymes
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do not form covalent bond with substrate
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Beriberi
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Lack of thiamine in diet. Thiamene pyrophosphate(TPP) is a co-enzyme that breaks C-C bonds.
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examples of oxidation-reduction coenzymes
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NAD+ and FAD. They don't bind covalently to substrate. They accept and donate electrons. Vitamin E and C are also ox-red coenzymes but can act as antioxidants to prevent free radical injury.
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alcohol dehydrogenase
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dimer
Zn with ser, his NAD+ is reduced Catalyzes ox of ethanol. Acetaldehyde is product |
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six enxyme classes
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oxidoreductases
transferases hydrolases lyases isomerases ligases |
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Acetaldehyde
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Product of ethanol oxidation.
highly reactive and toxic. cause of liver diseases in alcoholism. |
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metal ion catalysis
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mg2+ involved in binding phospohate to enzyme from coenzyme
ATP is usually bound to enzyme via Mg2+ alcoholdehydrogenase zn2+ |
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organophosphorus toxins
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Ex Sarin. Form intermediate with actylcholinesterase.
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asprin
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cox inhibitor
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Covalent inhibitors
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bind covalently to catalytic site. Ex asprin and sarin
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transition state analog inhibitors
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bind more tightly than substrate or product. Ex penicillin and allopurinol
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penicillin
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..
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allopurinol
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..
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heavy metal toxicity
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Mercury binds at SH groups of many enzymes
Lead replaces the normal functional metals in enzymes. aluminum interferes with iron transport and can cause anemia |
