9번
발문
제시된 그림은 fatty acid의 분해과정인 β-oxidation을 표시한다. ③번 반응을 일으키는 효소의 이름을 고르시오. (E, 2점)
(그림: β-oxidation 4단계 — ①→② acyl-CoA → trans-Δ²-enoyl-CoA, ②→③ enoyl-CoA → L-hydroxyacyl-CoA, ③→④ hydroxyacyl-CoA → ketoacyl-CoA, ④→① ketoacyl-CoA → acetyl-CoA + 단축된 acyl-CoA)
선지
① β-ketothiolase ② Acyl CoA dehydrogenase ③ Hydroxyacyl CoA dehydrogenase ④ Enoyl CoA hydratase ⑤ Acetyl CoA carboxylase
관련 내용
해설
정답: ③ Hydroxyacyl CoA dehydrogenase
β-oxidation 4단계 효소:
| 단계 | 반응 | 효소 | 보조인자 |
|---|---|---|---|
| ① | Acyl-CoA → trans-Δ²-enoyl-CoA | Acyl CoA dehydrogenase | FAD → FADH₂ |
| ② | trans-Δ²-enoyl-CoA → L-3-hydroxyacyl-CoA | Enoyl CoA hydratase | H₂O 첨가 |
| ③ | L-3-hydroxyacyl-CoA → 3-ketoacyl-CoA | Hydroxyacyl CoA dehydrogenase | NAD⁺ → NADH |
| ④ | 3-ketoacyl-CoA → acetyl-CoA + 단축 acyl-CoA | β-ketothiolase | CoA-SH |
그림의 ③번 반응: hydroxyacyl-CoA → ketoacyl-CoA (산화) → Hydroxyacyl CoA dehydrogenase (NADH 생성)
- ⑤ Acetyl CoA carboxylase는 지방산 합성 효소 (분해가 아님) ✗