HETEROLOGOUS EXPRESSION OF FUNCTIONALLY ACTIVE HUMAN CYTOCHROMES P450.2. MODELING OF XENOBIOTIC METABOLISM BY SACCHAROMYCES-CEREVISIAE CELLS EXPRESSING CYTOCHROME P450IIIA4

A cDNA encoding human cytochrome P450IIIA4 was modified by the PCR met hod for maximum expression in the Saccharomyces cerevisiae cells and r ecloned into a yeast expressing vector containing a galactose promoter . Expression of functionally active cytochrome P450IIIA4 was achieved in yeast cells. The protein showed a normal reduced CO spectrum in mic rosomes isolated from the induced yeast bearing the cytochrome P450III A4 gene. The microsomes catalyzed oxidative bioconversion of nifedipin e, a specific substrate for cytochrome P450IIIA4.