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28 Cards in this Set
- Front
- Back
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what family of enzymes participate in metabolism in up to 80% of prescription drugs?
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cytochromes P450
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1. What general reaction does a P450 system catalyze?
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Hydroxylation; X-H + O2 + NADPH + H+ X-OH + H2O + NADP+ (oxidized substrate)
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2. What prosthetic group is found in all P450 enzymes?
why are they called cytochromes? |
contain Heme
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3. Name four biological molecules that are substrates for P450 enzymes.
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1)Long chain fatty acids,
2)steroids, 3)bile salts, 4)Vitamin D, 5)heme |
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6. Describe the ways in which drugs can change the activities of P450 enzymes.
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Induction: some p450 enzymes are synthesized in response to the presence of their substrate.
due to the lax substrate specificity p450 enzymes may |
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7. Discuss the importance of P450 systems in drug metabolism. Include consideration of patient lifestyle and polypharmacy (many drugs).
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P450 can determine ½ lives of drugs in body and extent of drug activations, causes drug-drug interactions (can increase or decrease primary medication concentration in blood)
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8. What is the subcellular location of P450 systems in the liver?
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Liver= smooth ER
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8. What is the subcellular location of P450 systems in the adrenal?
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adrenal = mitochondrial membrane
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9. Discuss the factors that govern the levels of P450 activity.
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Genetic background, sex, age, pregnancy (hormones), nutritional status, disease (esp. liver and kidney)
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what family of enzymes participate in metabolism in up to 80% of prescription drugs?
|
cytochromes P450
|
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What 2 biochem aspects are responsible for cytochromes p450 enzyme family's ability to causes drug interactions, undesired effects, and idiosyncratic responses to medication
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1) relatively non-substrate specific enzyme
2) induced by their substrates or substrate analogues |
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1. What general reaction does a P450 system catalyze?
|
Hydroxylation; X-H + O2 + NADPH + H+ X-OH + H2O + NADP+ (oxidized substrate)
|
|
|
2. What prosthetic group is found in all P450 enzymes?
why are they called cytochromes? |
contain Heme
|
|
|
3. Name four biological molecules that are substrates for P450 enzymes.
|
1)Long chain fatty acids,
2)steroids, 3)bile salts, 4)Vitamin D, 5)heme |
|
|
6. Describe the ways in which drugs can change the activities of P450 enzymes.
|
Induction: some p450 enzymes are synthesized in response to the presence of their substrate.
due to the lax substrate specificity p450 enzymes may |
|
|
7. Discuss the importance of P450 systems in drug metabolism. Include consideration of patient lifestyle and polypharmacy (many drugs).
|
P450 can determine ½ lives of drugs in body and extent of drug activations, causes drug-drug interactions (can increase or decrease primary medication concentration in blood)
|
|
|
8. What is the subcellular location of P450 systems in the liver?
|
Liver= smooth ER
|
|
|
8. What is the subcellular location of P450 systems in the adrenal?
|
adrenal = mitochondrial membrane
|
|
|
9. Discuss the factors that govern the levels of P450 activity.
|
Genetic background, sex, age, pregnancy (hormones), nutritional status, disease (esp. liver and kidney)
|
|
|
What 2 biochem aspects are responsible for cytochromes p450 enzyme family's ability to causes drug interactions, undesired effects, and idiosyncratic responses to medication
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1) relatively non-substrate specific enzyme
2) induced by their substrates or substrate analogues |
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What class of reaction is catalyzed by the enzymes of the cytochrome p450 family?
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hydroxlyation
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one reason that cytochrome 450 activity is so difficult to predict is that the enzyme is
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inducible by its own substrate
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Where within the cell do cytochrome 450 occur?
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smooth ER
mitochondrial mebrane |
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All cytochrome 450 contain the prosthetic group
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heme
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are polysaccharides (glucose) a substrate of cytochrome 450?
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NO
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where is cytochrome 450 found in liver
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smooth ER
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The electron donor for most cytochrome 450-mediated reactions is
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NADPH
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Uncoupled cytochrome P450 enzymes are sometimes a source of ___ in vivo
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Hydrogen peroxide
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