Purine nucleotide metabolism in promastigotes of Leishmania tropica: inhibitory effect on allopurinol and analogues of purine nucleosides.

The catabolism of adenosine 5'-monophosphate in promastigotes of L. tropica suggests the presence of a parasite specific pathway. In continuing the investigation on enzymes of this pathway two purine nucleoside cleaving enzymes have been found, adenosine phosphorylase and inosine nucleosidase. Various purine nucleoside analogues inhibited the activity of both enzymes. A mode of action of the growth inhibition of L. tropica promastigotes by allopurinol has been suggested on the basis of Michaelis and inhibitor constants.