Isobutyrylcoenzyme A (isobutyryl-CoA) is a short-chain branched acyl CoA. Isobutyryl-CoA is a substrate for isobutyryl-CoA dehydrogenase (IBDH) in the catabolism of valine and an intermediate in the synthesis of isobutyryl-L-carnitine , which accumulates in IBDH deficiency.