Presence of proteins recognized by mammalian cytochrome P-450 antibodies in Euglena gracilis

Abstract

We have attempted to probe three microsomal cytochrome P-450 isozymes in Euglena gracilis using immunochemical methods. They cross-react with anti-rat cytochrome P4502C 11 cytochrome P4502E, and cytochrome P4502B. Activities of alkoxyphnoxazone dealkylation have been tested in living cells. In untreated cultures, the amount of proteins recognized by anti-cytochrome P4502C 11 or anti-cytochrome P450E is high. Phenobarbital treatment increased the level of microsomal proteins recognized by antibody to cytochrome P4502B, as well as dealkylases of pentoxyresorufin, but decreased the level of proteins recognized by anti-cytochrme P4502C 11 or cytochrome P4502E. These results suggest that these unicellular algae may contain different isozymes of microsomal cytochromes P-450, comparable to those in mammalian liver. They are cytochrome P-450 equivalents of mammalian isoenzymes 2C, 2E and 2B. However, we could not demonstrate ethanol induction of cytochrome P-450 equivalent to isoenzyme 2E. Its role in xeno- or endobiotic metabolism remains to be elucidated.