multiple cytochromes p-450 were present in human adults : isoenzymes involved in the metabolism of exogenous substrates such as ethylmorphine , hexobarbital , aniline and diazepam , and endogenous substrates were present and active in the fetus , whereas isoenzyme ( s ) permitting the hydroxylation of polycyclic aromatic hydrocarbons exhibited a very low activity .
C0010762
cytochromes p-450
C0025519
metabolism