The enzymes of purine salvage inTrypanosoma cruzi, Trypanosoma bruceiandLeishmania mexicana

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Abstract
SUMMARY: We have previously shown the presence of various purine salvage enzymes inTrypanosoma cruzi, including phosphoribosyltransferase, aminohydrolase, kinase, phosphorylase and hydrolase activities. We now report that a similar situation occurs inLeishmania mexicana amazonensisandTrypanosoma brucei brucei. In all three organisms we found higher levels of activity for the phosphoribosyltransferase enzymes than for the nucleoside kinases, suggesting a preference for the salvage of purine bases rather than nucleosides. Similarly, absence of inosine phosphorylase activity suggests that only one route for the salvage of hypoxanthine is available to the three organisms. The most striking difference was that whereasT. cruziandT. bruceipossessed adenosine aminohydrolase activity, this was not detected inL. mexicana; instead adenine amino-hydrolase activity was found. The overall similarity, as judged by the distribution of enzyme activities, of purine salvage in these three members of the kinetoplastida suggest a broad spectrum of activity for any inhibitor acting in this area; the plethora of alternative salvage pathways, however, suggests that in no case would such inhibition be cidal.