Enzymes

Question 1

NAD AND FAD are needed by what 2 enzymes?

Answer 1

Lactate DH and Succinate DH

Question 2

Lactate DH 1,2?
Lactate DH 5?
are indicators of

Answer 2

Myocardial infarction, Acute hepatitis

Question 3

Competitive inhibition:
Vmax …
Km …
Examples?

Answer 3

Vmax is the same
Km increases(less affinity)
Malonate inhibits Succinate DH, Sulfa drugs inhibit folic acid synthesis

Question 4

Non-competitive inhibition:
Vmax…
Km…
Examples?

Answer 4

Decreases
Stays the same
Lead inhibits ferrochelatase and alanine dehydratase, Caffeine inhibits PDE, protonating Asp in chymotrypsin.

Question 5

Irreversible competitive inhibition(2)…

Answer 5

1) Aspirin: Inhibits COX
2) Allopurinol: Inhibits Xanthine Oxidase(suicidal inhibition)

Question 6

Homotropic allosteric modulator vs heterotropic

Answer 6

resemble substrate, don’t

Question 7

Mechanisms of catalysis…(4)

Answer 7

1) Acid-Base: Keto > Enol, alpha-anomeric > B-anomeric, Ribonuclease
2) Proximity and Proper orientation: Lyzozyme peptidoglycan hydrolysis(D,E)(Chair vs half-boat)
3) Covalent: Aminotransferase
4) Metal: Carbonic anyhdrase

Question 8

Insulin favors…
Glucagon favors…

Answer 8

Phosphatases, Kinases

Question 9

Cholera toxin…

Answer 9

ADP ribosylation(covalent mod) at the Arg residue inhibits intrinsic GTPase of G(G alpha) protein. AC isn’t broken down and cAMP increases = diarrhea, and dehydration.