Reaction catalyzed by medium-chain acyl-CoA dehydrogenase (1.3.8.7), long-chain acyl-CoA dehydrogenase (1.3.8.8), very-long-chain acyl-CoA dehydrogenase (1.3.8.9)

		+		acceptor	=			+		reduced acceptor
	acyl-CoA	+		acceptor	=		2,3-dehydroacyl-CoA	+		reduced acceptor