Isobutyryl-CoA dehydrogenase which catalyzes the conversion of 2-methylpropanoyl-CoA to (2E)-2-methylpropenoyl-CoA in the valine catabolic pathway (PubMed:11013134, PubMed:12359132, PubMed:16857760). To a lesser extent, also able to catalyze the oxidation of (2S)-2-methylbutanoyl-CoA (PubMed:11013134, PubMed:12359132).
