Folate Metabolism in Filariae: Enzymes Associated with 5,10-Methylenetetrahydrofolate

Adult Brugia pahangi and Dirofilaria immitis were found to possess the following four enzymes that are associated with the cofactor 5,10-methylenetetrahydrofolate (CH2FH4): serine hydroxymethyltransferase, thymidylate synthetase, CH2FH4dehydrogenase, and CH2FH4reductase. The properties of the isoenzymes from the two filariae were virtually indistinguishable, except that diethylcarbamazine inhibited CH2FH4reductase from B. pahangi 50% at 10 μ M, but did not affect the isoenzyme from D. immitis at 100 μ M. The properties of these four filarial enzymes generally were similar to their counterparts from mosquitoes and mammalian sources, but several notable differences were identified.