In enzymology, a 3-methyl-2-oxobutanoate dehydrogenase is an enzyme that catalyzes the chemical reaction The 3 substrates of this enzyme are 3-methyl-2-oxobutanoate, dihydrolipoyllysine-residue (2-methylpropanoyl)transferase, and lipoyllysine, whereas its 3 products are dihydrolipoyllysine-residue (2-methylpropanoyl)transferase, S-(2-methylpropanoyl)dihydrolipoyllysine, and CO2. This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with a disulfide as acceptor. This enzyme participates in valine, leucine and isoleucine degradation. It employs one cofactor, thiamin diphosphate. It is the E1 subunit of a catalytic complex.

Structural studies

As of late 2007, twenty-nine structures have been solved for this class of enzymes, with PDB accession codes, , , , , , , , , , , , , , , , , , , , , , , , , , , , and.