Acetyl CoA carboxylase (ACC) is an essential enzyme found in all living organisms, including animals, plants, fungi, and bacteria. It plays a crucial role in fatty acid metabolism by catalyzing the carboxylation of Acetyl CoA to Malonyl CoA, a key regulatory step in fatty acid synthesis.
The enzyme ACC is made up of multiple subunits, with variations in subunit composition among different organisms. The major subunits include biotin carboxyl carrier protein (BCCP), biotin carboxylase (BC), and carboxyltransferase (CT). BCCP acts as a shuttle to transfer the carboxyl group from bicarbonate to the active site of the enzyme, BC catalyzes the carboxylation of biotin, and CT transfers the carboxyl group from biotin to Acetyl CoA.
ACC is regulated by multiple mechanisms to meet the varying demands of fatty acid synthesis. Hormonal regulation is a major pathway controlling ACC activity, with insulin stimulating its activation and glucagon inhibiting it. Phosphorylation of ACC also plays a role in its regulation, where AMP-activated protein kinase (AMPK) phosphorylates and inactivates ACC during energy-limited conditions.
Overall, the role of Acetyl CoA carboxylase in fatty acid metabolism is vital for the synthesis of lipids, which serve as structural components of cells and as sources of energy. Understanding the precise regulation and mechanisms of ACC activity has significant implications in various fields, including metabolism research, drug development, and agriculture.
