The enzyme is CoA-dependent and contains thiamine diphosphate and iron-sulfur clusters. Preferentially utilizes 2-oxo-acid derivatives of branched chain amino acids, e.g. 3-methyl-2-oxopentanoate, 4-methyl-2-oxo-pentanoate, and 2-oxobutanoate. This enzyme is a member of the 2-oxoacid oxidoreductases, a family of enzymes that reversibly catalyse the oxidative decarboxylation of different 2-oxoacids to form their CoA derivatives, and are differentiated based on their substrate specificity. For examples of other members of this family, see EC 1.2.7.1, pyruvate synthase, and EC 1.2.7.3, 2-oxoglutarate synthase.
