acetilCoAkarboxiláz

Acetyl-CoA carboxylase, often abbreviated as ACC, is a vital enzyme in the synthesis of fatty acids. It plays a crucial role in the first committed step of lipogenesis, the metabolic pathway responsible for creating fat. ACC catalyzes the carboxylation of acetyl-CoA to malonyl-CoA, using bicarbonate as the carbon source and requiring ATP hydrolysis for energy. This reaction is highly regulated, making ACC a key control point for fatty acid synthesis in both animals and plants.

In animals, ACC exists in several isoforms, with ACC1 and ACC2 being the most prominent. ACC1 is primarily found in the cytoplasm and is the main enzyme involved in fatty acid synthesis. ACC2 is located in the mitochondrial outer membrane and is thought to play a role in regulating fatty acid oxidation. The activity of ACC is subject to both allosteric regulation and covalent modification, particularly through phosphorylation and dephosphorylation by various signaling pathways. For example, insulin promotes dephosphorylation, thus activating ACC and stimulating fatty acid synthesis, while glucagon and epinephrine tend to activate AMP-activated protein kinase (AMPK), which phosphorylates and inhibits ACC.

In plants, ACC is also essential for fatty acid synthesis, particularly in the production of seed oils. Similar to animals, plant ACC is regulated by phosphorylation. Disruptions in ACC function can have significant metabolic consequences, impacting energy storage, cellular membrane integrity, and signaling processes. Its importance in lipogenesis makes ACC a significant target for drug development, particularly for metabolic disorders like obesity and type 2 diabetes.