beta oxidation of fats

Question 1

Site of β-oxidation?

Answer 1

“Mitochondrial matrix (activated by carnitine shuttle).”

Question 2

Step 1 of β-oxidation?

Answer 2

“Oxidation: Acyl-CoA → trans-Δ²-enoyl-CoA (FADH₂ produced

Question 3

Step 2 of β-oxidation?

Answer 3

“Hydration: trans-Δ²-enoyl-CoA → L-β-hydroxyacyl-CoA (enzyme: enoyl-CoA hydratase).”

Question 4

Step 3 of β-oxidation?

Answer 4

“Oxidation: L-β-hydroxyacyl-CoA → β-ketoacyl-CoA (NADH produced

Question 5

Step 4 of β-oxidation?

Answer 5

“Cleavage: β-ketoacyl-CoA → acetyl-CoA + acyl-CoA (2C shorter

Question 6

Net ATP per palmitate (16C)?

Answer 6

“106 ATP (7 cycles → 8 acetyl-CoA

Question 7

Regulation of CPT-1 (CAT-1)?

Answer 7

“Inhibited by malonyl-CoA (fed state). Stimulated by fasting/glucagon (↓malonyl-CoA).”

Question 8

Regulation of β-hydroxyacyl-CoA dehydrogenase?

Answer 8

“Primarily substrate-dependent (no allosteric regulation).”

Question 9

Rate-limiting step of β-oxidation?

Answer 9

“Carnitine shuttle (CPT-1 activity).”

Question 10

Clinical defect in CPT-1?

Answer 10

“Hypoketotic hypoglycemia (can’t transport LCFAs into mitochondria).”