Catalyzes the oxidative decarboxylation of glutaryl-CoA to crotonyl-CoA and CO(2) in the degradative pathway of L-lysine, L-hydroxylysine, and L-tryptophan metabolism. It uses electron transfer flavoprotein as its electron acceptor. Isoform Short is inactive. glutaryl-CoA + 2 H(+) + oxidized [electron-transfer flavoprotein] = (2E)-butenoyl-CoA + CO2 + reduced [electron-transfer flavoprotein] Strongly inhibited by MCPA-CoA, a metabolite of hypoglycin which is present in unripened fruit of the ackee tree. Release of crotonyl-CoA product from the enzyme is the rate-determining step in its steady-state turnover. Amino-acid metabolism; lysine degradation. Amino-acid metabolism; tryptophan metabolism. Homotetramer. Isoform Long and isoform Short are expressed in fibroblasts and liver. The disease is caused by variants affecting the gene represented in this entry. Belongs to the acyl-CoA dehydrogenase family.