Fatty acid
In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with a long aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually not found in organisms, but instead as three main classes of esters: triglycerides, phospholipids, and cholesterol esters. In any of these forms, fatty acids are both important dietary sources of fuel for animals and they are important structural components for cells.
Enoyl-CoA hydratase
ECH catalyzes the second step (hydratation) in the breakdown of fatty acids (β-oxidation). Fatty acid metabolism is how human bodies turn fats into energy. Fats in foods are generally in the form of triglycerols. These must be broken down in order for the fats to pass into human bodies. When that happens, three fatty acids are released.