The biotransformation of tranylcypromine by Cunninghamella echinulata

When incubated alone for 7 days with the fungus Cunninghamella echinulata, tranylcypromine was extensively metabolized. As observed in mammalian systems, N-acetyltranylcypromine was the major metabolite recovered along with lesser amounts of 4-hydroxytranylcypromine, as its N,O-diacetyl derivative. The rate and extent of tranylcypromine biotransformation was affected by whether incubation was on either 30° or flat brackets with a gyratory shaker. There is a strong association between the rate of biotransformation and the utilization of glucose, formation of ammonia, and pH. The slowest rates of biotransformation and metabolic response were observed with the large fungal pellets formed during incubation on flat brackets. These findings raise the possibility that, as in mammalian systems, fungal metabolism of xenobiotics can be affected by nutrient and environmental conditions. Key words: Cunninghamella echinulata, tranylcypromine, biotransformation, toxicity model.