Enoyl Coenzyme A hydratase, short chain 1 mitochondrial, also known as ECHS1, is a member of the hydratase/isomerase superfamily. It localizes to the mitochondrial matrix. Expressed in muscle, liver and fibroblasts, with low expression in kidney and spleen, ECHS1 exists as a homohexamer that functions in the second step of the mitochondrial fatty acid β-oxidation pathway. Recombinant human ECHS1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.