Lipogeneesiin

Lipogeneesiin is the metabolic process by which fatty acid synthesis occurs. It is the process of converting carbohydrates, some amino acids, and alcohol into fatty acids, which are then stored as triglycerides in adipose tissue. This process primarily takes place in the cytoplasm of cells, particularly in the liver, adipose tissue, and mammary glands.

The key enzyme in lipogenesis is acetyl-CoA carboxylase (ACC), which catalyzes the first committed step: the carboxylation of acetyl-CoA to malonyl-CoA. This reaction requires biotin as a cofactor and consumes ATP. Following the formation of malonyl-CoA, a multi-enzyme complex known as fatty acid synthase (FAS) takes over. FAS elongates the fatty acid chain by adding two-carbon units derived from acetyl-CoA, using NADPH as a reducing agent. The process repeats until a 16-carbon saturated fatty acid, palmitate, is produced. Palmitate can then be further elongated or desaturated to form other fatty acids.

Lipogenesis is an anabolic pathway, meaning it builds larger molecules from smaller ones. It is regulated by hormonal signals, with insulin promoting lipogenesis and glucagon and adrenaline inhibiting it. This regulation ensures that energy is stored efficiently when nutrient availability is high and mobilized when energy is needed. While essential for energy storage and cell membrane integrity, excessive lipogenesis can contribute to obesity and related metabolic disorders like fatty liver disease.