Developmental change in the apparent kinetic properties of drug-oxidizing enzymes in the human liver.

When analyzing the effect of substrate concentration on the reaction rate of aminopyrine N-demethylation, aniline p-hydroxylation, and 3,4-benzpyrene hydroxylation by human fetal and adult liver samples we found that Lineweaver-Burk and Eadie-Hofstee analyses yielded mostly linear lines with fetal liver, but nonlinear lines with adult livermthis may be taken to indicate that a qualitative change in drug-oxidizing enzymes of the human liver occurs during ontogenetic development, of the human liver occurs during ontogenetic development, possibly so that during the fetal period liver contains one ana during the adult period two enzymes metabolizing aminopyrine, anilinw, and 3,4-benzpyrene.