β-ketoacyl-ACP reductase

Definition

β-ketoacyl-ACP reductase is an enzyme involved in the biosynthesis of fatty acids. It catalyzes the reduction of a β-ketoacyl intermediate to a β-hydroxyacyl intermediate, an important step in the fatty acid synthesis pathway.

5 Must Know Facts For Your Next Test

1. β-ketoacyl-ACP reductase is a key enzyme in the fatty acid synthesis cycle, responsible for the reduction of β-ketoacyl-ACP intermediates.
2. The reaction catalyzed by β-ketoacyl-ACP reductase utilizes NADPH as a cofactor to reduce the β-keto group to a β-hydroxyl group.
3. This reduction step is necessary to prepare the fatty acid chain for the subsequent dehydration and enoyl reduction steps in the synthesis cycle.
4. Disruption of β-ketoacyl-ACP reductase activity can lead to the accumulation of β-ketoacyl-ACP intermediates and impair overall fatty acid synthesis.
5. The enzyme is a member of the short-chain dehydrogenase/reductase (SDR) family and shares structural and mechanistic similarities with other SDR enzymes.

Review Questions

• Explain the role of β-ketoacyl-ACP reductase in the context of fatty acid biosynthesis.
  • β-ketoacyl-ACP reductase is a critical enzyme in the fatty acid synthesis pathway. It catalyzes the reduction of a β-ketoacyl-ACP intermediate to a β-hydroxyacyl-ACP intermediate, using NADPH as a cofactor. This reduction step is necessary to prepare the fatty acid chain for the subsequent dehydration and enoyl reduction reactions, ultimately leading to the elongation of the fatty acid chain. The activity of β-ketoacyl-ACP reductase is essential for the efficient and continuous synthesis of fatty acids in the cell.
• Describe the relationship between β-ketoacyl-ACP reductase and the broader fatty acid synthase complex.
  • β-ketoacyl-ACP reductase is one of the enzymatic components of the multi-enzyme fatty acid synthase complex. This complex coordinates the various steps of fatty acid biosynthesis, including the initial condensation of acetyl-CoA and malonyl-CoA, the reduction of the β-keto group by β-ketoacyl-ACP reductase, the dehydration, and the final enoyl reduction. The activity of β-ketoacyl-ACP reductase is therefore tightly integrated with the overall function of the fatty acid synthase complex, ensuring the efficient and sequential elongation of the growing fatty acid chain.
• Analyze the potential consequences of disrupting the activity of β-ketoacyl-ACP reductase in the context of cellular metabolism.
  • If the activity of β-ketoacyl-ACP reductase is disrupted, it would lead to the accumulation of β-ketoacyl-ACP intermediates within the fatty acid synthesis pathway. This disruption would impair the overall efficiency of fatty acid biosynthesis, as the subsequent dehydration and enoyl reduction steps would be hindered. The inability to properly reduce the β-keto group would limit the ability to elongate fatty acid chains, potentially leading to altered lipid profiles and imbalances in cellular metabolism. This could have far-reaching consequences on various physiological processes that rely on the availability of fatty acids, such as energy production, membrane structure, and signaling pathways.

Related terms

Fatty Acid Synthase: A multi-enzyme complex that catalyzes the complete synthesis of fatty acids from acetyl-CoA and malonyl-CoA precursors.

Acyl Carrier Protein (ACP): A small, acidic protein that shuttles growing fatty acid chains between the different catalytic sites of the fatty acid synthase complex.

Malonyl-CoA: The activated form of malonic acid that serves as an extender unit for fatty acid chain elongation.