Kinetic characterization of inosine monophosphate dehydrogenase of Leishmania donovani.

Trypanosomatid protozoan pathogens are purine auxotrophs that are highly dependent on the enzyme inosine monophosphate dehydrogenase (IMPDH) for the synthesis of guanylate nucleotides. Enzymatic characterization of the Leishmania donovani IMPDH (LdIMPDH) overexpressed in E. coli revealed that this enzyme was highly specific for the substrates IMP and NAD(+) with K(m)(app) values of 33 and 390 microM, respectively.