Fatty acid degradation
Fatty acid degradation is the process in which fatty acids are broken down into their metabolites, in the end generating acetyl-CoA, the entry molecule for the citric acid cycle, the main energy supply of living organisms, including bacteria and animals. It includes three major steps: Lipolysis of and release from adipose tissue Activation and transport into mitochondria β-oxidation Lipolysis and release Initially in the process of degradation, fatty acids are stored in adipocytes. The breakdown of this fat is known as lipolysis. The products of lipolysis, free fatty acids, are released into the bloodstream and circulate throughout the body. During the breakdown of triacylglycerols into fatty acids, more than 75% of the fatty acids are converted back into triacylglycerol, a natural mechanism to conserve energy, even in cases of starvation and exercise. Activation and transport into mitochondria Fatty acids must be activated before they can be carried into the mitochondria, where fatty acid oxidation occurs. This process occurs in two steps catalyzed by the enzyme fatty acyl-CoA synthetase. Formation of an activated thioester bond The enzyme first catalyzes nucleophilic attack on the α-phosphate of ATP to form pyrophosphate and an acyl chain linked to AMP. The next step is formation