The long‐chain 3‐hydroxyacyl‐CoA dehydrogenase of human liver mitochondria

The mitochondrial/?-oxidation of fatty acids in neonatal liver is of major importance in energy generation, especially during milk feeding. Inherited disorders of mitochondrial/~-oxidation are life-threatening and relatively common (Pollitt, 1989), but are difficult to diagnose. In part this is because they could be caused by the absence of any of the chain-length-specific enzymes catalysing the four steps of the pathway. Our aim was to establish that human liver mitochondria contain long- and shortchain-specific 3-hydroxyacyl-CoA dehydrogenases. The short-chain-specific enzyme has been extensively studied but little is known about the long-chain enzyme. Absence of the latter from liver is suggested as a cause of some cases of hypoglycaemic 3hydroxydicarboxylic aciduria (Pollitt, 1990).