key term - $\beta$-ketoacyl ACP reductase

Definition

$\beta$-ketoacyl ACP reductase is an enzyme that plays a crucial role in the biosynthesis of fatty acids. It is responsible for the reduction of $\beta$-ketoacyl acyl carrier protein (ACP) intermediates during the fatty acid elongation cycle, which is a key step in the overall process of fatty acid synthesis.

5 Must Know Facts For Your Next Test

1. $\beta$-ketoacyl ACP reductase catalyzes the reduction of the $\beta$-keto group of the $\beta$-ketoacyl ACP intermediate, converting it to a $\beta$-hydroxy acyl ACP.
2. This reduction step is an essential part of the fatty acid elongation cycle, as it prepares the intermediate for the subsequent dehydration and enoyl reduction steps.
3. The $\beta$-ketoacyl ACP reductase enzyme utilizes NADPH as a cofactor, providing the reducing power necessary for the reduction reaction.
4. The activity of $\beta$-ketoacyl ACP reductase is tightly regulated to ensure the efficient and controlled synthesis of fatty acids.
5. Disruption of $\beta$-ketoacyl ACP reductase function can lead to alterations in fatty acid composition and potentially impact various metabolic processes.

Review Questions

• Explain the role of $\beta$-ketoacyl ACP reductase in the biosynthesis of fatty acids.
  • The $\beta$-ketoacyl ACP reductase enzyme plays a crucial role in the fatty acid elongation cycle by catalyzing the reduction of the $\beta$-keto group of the $\beta$-ketoacyl ACP intermediate. This reduction step converts the $\beta$-keto group to a $\beta$-hydroxy group, preparing the intermediate for the subsequent dehydration and enoyl reduction steps. The activity of $\beta$-ketoacyl ACP reductase is essential for the efficient and controlled synthesis of fatty acids, as it ensures the progression of the elongation cycle.
• Describe the relationship between $\beta$-ketoacyl ACP reductase and the Acyl Carrier Protein (ACP) in the context of fatty acid biosynthesis.
  • The $\beta$-ketoacyl ACP reductase enzyme specifically acts on $\beta$-ketoacyl ACP intermediates during the fatty acid elongation cycle. The Acyl Carrier Protein (ACP) is a small, acidic protein that serves as a cofactor, carrying the growing fatty acid chains throughout the biosynthesis process. The $\beta$-ketoacyl ACP reductase enzyme recognizes and catalyzes the reduction of the $\beta$-keto group on the ACP-bound fatty acid intermediate, enabling the continuation of the elongation cycle and the eventual synthesis of longer fatty acid molecules.
• Analyze the importance of the NADPH cofactor in the reaction catalyzed by $\beta$-ketoacyl ACP reductase and its implications for fatty acid biosynthesis.
  • The $\beta$-ketoacyl ACP reductase enzyme requires NADPH as a cofactor to provide the reducing power necessary for the reduction of the $\beta$-keto group on the ACP-bound fatty acid intermediate. NADPH serves as the source of hydride ions that are transferred to the $\beta$-keto group, converting it to a $\beta$-hydroxy group. This reduction step is a critical part of the fatty acid elongation cycle, as it prepares the intermediate for the subsequent dehydration and enoyl reduction reactions. The availability and regulation of NADPH, which is often linked to the cell's overall metabolic state, can directly impact the activity of $\beta$-ketoacyl ACP reductase and, consequently, the efficiency and rate of fatty acid biosynthesis.

Related terms

Acyl Carrier Protein (ACP): Acyl Carrier Protein (ACP) is a small, acidic protein that acts as a cofactor, carrying growing fatty acid chains during the biosynthesis of fatty acids.

Fatty Acid Elongation Cycle: The fatty acid elongation cycle is a series of enzymatic reactions that sequentially add two-carbon units to a growing fatty acid chain, resulting in the synthesis of longer fatty acids.

NADPH:

NADPH is a reduced form of nicotinamide adenine dinucleotide phosphate (NADP+), which serves as a cofactor for various enzymatic reactions, including the reduction catalyzed by $\beta$-ketoacyl ACP reductase.