Genetically engineered V79 Chinese hamster cells for stable expression of human cytochrome P450IA2.

V79 Chinese hamster cells were genetically engineered for stable expression of human P450IA2. Full length cDNA, encoding human P450IA2, was inserted into an SV40 early promoter containing eukaryotic expression vector and cointroduced with the selection marker neomycin phosphotransferase (conferring resistance to the neomycin derivative G418) into V79 Chinese hamster cells. The recombinant expression vector was introduced into two different V79 sublines, one expressing an endogenous acetyltransferase (V79-NH), the other not (V79-MZ).

Ontogeny of monooxygenase activities in the marmoset monkey (Callithrix jacchus).

The pre- and postnatal development of monooxygenases in the liver and adrenal gland of marmoset monkeys (Callithrix jacchus) was investigated. Cytochrome P450 was detected in the fetal adrenal gland, but aldrin epoxidase, ethoxycoumarin O-deethylase, and ethoxyresorufin O-deethylase activities were below detection limits. Although fetal hepatic cytochrome P450 was not detected, low activities of aldrin epoxidase and ethoxycoumarin O-deethylase, but no ethoxyresorufin O-deethylase, could be detected in fetal liver.

Purification and properties of cytochrome P-450 from liver microsomes of phenobarbital-treated marmoset monkeys (Callithrix jacchus).

One form of cytochrome P-450 from phenobarbital-induced marmoset liver was purified to apparent electrophoretic homogeneity and compared with the major inducible form isolated from rat liver. Whereas spectral properties and molecular weights, as well as catalytic activities towards aminopyrine and ethylmorphine N-demethylation are quite similar, rates of O-dealkylation with enzymes from the two species are considerably different. While ethoxycoumarin deethylation for the marmoset cytochrome is about one-fortieth of that for the rat, ethoxyresorufin and even pentoxyresorufin dealkylations for the marmoset form are not detectable.