StearoylCoAACP

Stearoyl-CoA:ACP desaturase, often abbreviated as SAD or Stearoyl-CoA desaturase, is a key enzyme in fatty acid biosynthesis. It belongs to the family of delta-9 desaturases. Its primary function is to introduce a double bond into the stearoyl-acyl carrier protein (ACP) molecule, converting it into oleoyl-ACP. This process is crucial for the synthesis of monounsaturated fatty acids, which play diverse roles in cellular membranes, energy storage, and signaling pathways.

The reaction catalyzed by stearoyl-CoA:ACP desaturase involves the oxidation of stearoyl-ACP. It uses molecular oxygen and NADH or NADPH as cofactors. The enzyme inserts a cis double bond between the ninth and tenth carbon atoms of the stearoyl chain, counting from the carboxyl end. This specific position is referred to as the delta-9 position. The resulting oleoyl-ACP is then further processed by other enzymes to yield oleic acid, a common monounsaturated fatty acid found in plants and animals.

Stearoyl-CoA:ACP desaturase is widely conserved across many organisms, highlighting the fundamental importance of monounsaturated fatty acids. In plants, this enzyme is vital for the production of various seed oils. In animals, it contributes to the overall fatty acid composition and influences membrane fluidity and lipid metabolism. Disruptions in the activity of stearoyl-CoA:ACP desaturase can have significant metabolic consequences, affecting cellular function and organismal health. Its regulation is often tied to nutritional status and developmental cues.