3-oxoacyl-(acyl-carrier-protein) reductase

Structure of 3-oxoacyl-(acyl-carrier-protein) reductase

Reaction catalyzed by 3-oxoacyl-(acyl-carrier-protein) reductase

3-oxoacyl-(acyl-carrier-protein) reductase is an enzyme that plays a crucial role in the fatty acid synthesis pathway. It is responsible for the reduction of 3-oxoacyl-ACP to 3-hydroxyacyl-ACP, a key step in the elongation cycle of fatty acid biosynthesis.

Function

3-oxoacyl-(acyl-carrier-protein) reductase catalyzes the NADPH-dependent reduction of 3-oxoacyl-ACP to 3-hydroxyacyl-ACP. This reaction is essential for the continuation of the fatty acid elongation process, which occurs in the cytoplasm of cells. The enzyme ensures the conversion of the keto group to a hydroxyl group, facilitating the subsequent dehydration and reduction steps that lead to the formation of saturated fatty acids.

Mechanism

The enzyme operates by binding to the 3-oxoacyl-ACP substrate and facilitating the transfer of electrons from NADPH to the keto group, reducing it to a hydroxyl group. This reaction is stereospecific, producing a specific stereoisomer of the 3-hydroxyacyl-ACP product. The active site of the enzyme contains residues that are critical for substrate binding and catalysis, ensuring high specificity and efficiency of the reaction.

Structure

3-oxoacyl-(acyl-carrier-protein) reductase is a member of the short-chain dehydrogenase/reductase (SDR) family. It typically consists of a single polypeptide chain that folds into a characteristic Rossmann fold, which is involved in binding the NADPH cofactor. The enzyme's structure is highly conserved across different species, reflecting its essential role in fatty acid metabolism.

Biological Importance

The activity of 3-oxoacyl-(acyl-carrier-protein) reductase is vital for the synthesis of long-chain fatty acids, which are important components of cell membranes, energy storage molecules, and signaling molecules. Disruptions in the function of this enzyme can lead to metabolic disorders and have been implicated in various diseases.

Related Enzymes

3-oxoacyl-(acyl-carrier-protein) reductase is part of a larger family of enzymes involved in fatty acid synthesis, including acetyl-CoA carboxylase, malonyl-CoA:ACP transacylase, and enoyl-ACP reductase. These enzymes work in concert to elongate fatty acid chains by two carbon units per cycle.

Related Pages

• Fatty acid synthesis
• Acyl carrier protein
• NADPH
• Dehydrogenase