Comparative properties of schistosomal and filarial dihydrofolate reductases.

摘要: Abstract Dihydrofolate (DHF) reductase activity was detected in crude extracts of four species adult filarial worms ( Dirofilaria immitis, Litomosoides carinii, Dipetalonema witei, and Onchocerca volvulus ) the blood fluke Schistosoma mansoni ). The filariae were much richer sources enzyme than schistosomes. Lyophilized D. immitis L. carinii as rich a source comparable numbers their living counterparts subsequently subjected to acetone powdering. Furthermore, females both these contained more twice DHF per milligram protein those males. apparent K m value schistosomal all reductases for approximately 5 × 10 −6 M, while that parasites' NADPH range 1–3 −5 M. Their molecular weights around 20,000. Both showed similar patterns sensitivity various drugs generally less sensitive analogous mammalian inhibition by most presently available inhibitors. Methotrexate related 2,4-diaminoquinazoline (CCNSC 529,861) potent inhibitors among 14 compounds tested, causing 50 cent −8 M −10 However, two roughly equipotent against enzymes, quinazoline derivative significantly enzymes. In terms ID , 2,4-diaminopyrimidine trimethoprim. On same basis, suramin, especially from O. this case being 2 compared with 7 reductase.