PHASE-I AND PHASE-II ENZYMES PRODUCED BY CUNNINGHAMELLA-ELEGANS FOR THE METABOLISM OF XENOBIOTICS

The filamentous fungus Cunninghamella elegans has the ability to metab olize xenobiotics, including polycyclic aromatic hydrocarbons and phar maceutical drugs, by both phase I and II biotransformations. Cytosolic and microsomal fractions were assayed for activities of cytochrome P4 50 monooxygenase, aryl sulfotransferase, glutathione S-transferase, UD P-glucuronosyltransferase, UDP-glucosyltransferase, and N-acetyltransf erase. The cytosolic preparations contained activities of an aryl sulf otransferase (15.0 nmol min(-1) mg(-1)), UDP-glucosyltransferase (0.27 nmol min(-1) mg(-1)) and glutathione S-transferase (20.8 nmol min(-1) mg(-1)). In contrast, the microsomal preparations contained cytochrom e P450 monooxygenase activities for aromatic hydroxylation (0.15 nmol min(-1) mg(-1)) and N-demethylation (0.17 nmol min(-1) mg(-1)) of cycl obenzaprine. UDP-glucuronosyltransferase activity was detected in both the cytosol (0.09 nmol min(-1) mg(-1)) and the microsomes (0.13 nmol min(-1) mg(-1)). N-Acetyltransferase was not detected. The results fro m these experiments provide enzymatic mechanism data to support earlie r studies and further indicate that C. elegans has a broad physiologic al versatility in the metabolism of xenobiotics.