The carbon chain of fatty acids is shortened by 2 carbon atoms at a time. This involves successive reactions catalysed by 4-enzymes. These act the following order: (A) Acetyl CoA dehydrogenase, β-OH acyl CoA dehydrogenase, enoyl hydrase, thiolose (B) Acyl CoA dehydrogenase, thiolase, enoyl hydrase, β-OH acyl CoA dehydrogenase (C) Acyl CoA dehydrogenase, thiolose, enoyl hydrase, β-OH acyl CoA dehydrogenase (D) Enoyl hydrase, β-OH acyl CoA dehydrogenase, acyl CoA dehydrogenase, thiolose,