Characterization of a mutant Leishmania donovani deficient in adenosine kinase activity

David M. Iovannisci, Buddy Ullman

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

From a mutagenized population of wildtype Leishmania donovani promastigotes, a clonal cell line, TUBA2, was isolated by virtue of its ability to survive and grow in 20 μM tubercidin (7-deazaadenosine). The TUBA2 clone was also 1000-fold less sensitive than the parental line to growth inhibition by formycin A, another cytotoxic adenosine analog. Parental and mutant cells, however, were equally sensitive to growth inhibition by formycin B, allopurinol riboside, and 6-thioguanosine. Mutant cell extracts, unlike those prepared from wildtype cells, did not phosphorylate radiolabelled adenosine, tubercidin, or formycin A. Intact adenosine kinase-deficient cells did not accumulate exogenous tubercidin or formycin A but incorporated [14C]adenosine at rates 25% of those found for parental cells. The uptake data suggest that adenosine kinase plays an important role in the metabolism of adenosine but indicate alternative metabolic pathways for this nucleoside. The metabolism of adenosine to the nucleotide level in TUBA2 cells appears to be initiated via deribosylation to adenine. Significant amounts of both adenosine hydrolytic and adenosine phosphorylytic activities have been detected in L. donovani promastigotes. Furthermore, L. donovani extracts could slowly catalyze the deamination of formycin A. The isolation and characterization of adenosine kinase-deficient cells has provided considerable insight into the function of the purine pathway in L. donovani.

Original languageEnglish (US)
Pages (from-to)139-151
Number of pages13
JournalMolecular and Biochemical Parasitology
Volume12
Issue number2
DOIs
StatePublished - Jun 1984

Keywords

  • Genetics
  • Leishmania donovani
  • Purine metabolism

ASJC Scopus subject areas

  • Parasitology
  • Molecular Biology

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