Presence and Properties of Thymidine Phosphorylase in Echinococcus granulosus Protoscoleces

Abstract

The present investigation indicates the presence of thymidine phosphorylase (TPase) (EC.2.4.2.4) and its activity in supernatant fraction of Echinococcus granulosus protoscoleces extract, furthermore some of its kinetics properties were investigated. It was found that deoxyuridine might be an alternative substrate for thymidine during catalyzed reaction by enzyme Tpase. The result also indicated that TPase activity was extremely sensitive to inhibite by thymine(product reaction), cytidine, 5-flourouracil and albendazole with inhibitory percentages of: 36%, 68%, 52% and 3% respectively. The presence of TPase activity indicates the presence of salvage pathway for thymine nucleotide which was essential to deoxyribonucleic acid (DNA) synthesis in this organism, in addition to de novo pathway.