Glutaryl-CoA dehydrogenase (GCD). GCD is an acyl-CoA dehydrogenase, which catalyzes the oxidative decarboxylation of glutaryl-CoA to crotonyl-CoA and carbon dioxide in the catabolism of lysine, hydroxylysine, and tryptophan. It uses electron transfer flavoprotein (ETF) as an electron acceptor. GCD is a homotetramer. GCD deficiency leads to a severe neurological disorder in humans.