Exhibits a high coumarin 7-hydroxylase activity. an organic molecule + O2 + reduced [NADPH--hemoprotein reductase] = an alcohol + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Liver, with a strong circadian rhythmicity. Circadian expression is regulated by DBP. In liver; activity 6 fold higher in females than in males. There are only 11 differences between the sequence of testosterone 15-alpha-hydroxylase and that of coumarin 7-hydroxylase. By site-directed mutagenesis it has been shown that modification of position 209 is sufficient to convert the specificity of the two forms of the enzyme. Belongs to the cytochrome P450 family.