Hepatic Metabolism

Question 1

Km

Answer 1

Michaelis mention constant: the conc of drug that causes he enzyme to turnover at half it’s maximum rate

Question 2

Phase 1 met

Answer 2

Oxidation
Reduction
Hydrolysis
Isomerisation

Question 3

Example of phase 1 drug metabolism

Answer 3

Hepatic esterae converts ramipril (et-cooh) to ramiplilat (cooh) the active de-esterified drug

Question 4

Phase 2 metabolism

Answer 4

Conjugation reaction

1. Adds water soluble chemical group (glucuronide and sulphate group)
2. De activates drug by removing or substituting the chemical reactive group

Question 5

Addpoc of aspirin

Answer 5

Duh

Question 6

Cyp450

Answer 6

Couple of haem protein enzymes

Drugs bind to its active site of the enzyme causes a conformational change in the proteins stricture.
A proximal redox active iron atom suspended in a porphyrin ring, catalysed the oxidation of the drug.

Question 7

Cyp and drugs

Answer 7

Cyp1a2 - caffeine and theophylline

Cyp1a1 - theophylline

Question 8

Ugt1a1

Answer 8

Phase 2 enzyme, causes glucuronidation of (bilirubin and udp- glucuronic acid) to bilirubin glucuronide (water soluble)

Question 9

Udp glucuronosyl transferase is dysfunctional in?

Answer 9

Gilbert’s and chigger najar

Question 10

Carbamazepine induces?

Answer 10

Cyp3a4 that metabolises rifampin in also

Question 11

Erythromycin

Answer 11

Inhibits cyp3a4 and causes a build up of doxorubicin

Question 12

Paracetamol overdose

Answer 12

Alcohol causes 2e1 and 1a2 to increase. This causes more phase 1 intermediates of paracetamol (n-acetyl-p-benzo-quinoneimine)

Glutathione acts by joinjng to napbqi and stoping it’s toxic effects. As there’s too much napbqi, glutathione reserves rapidly deplete allowing napbqi to cause damage to the hepatocytes.