An acidocalcisomal exopolyphosphatase from Leishmania major with high affinity for short chain polyphosphate

Claudia O. Rodrigues, Felix A. Ruiz, Mauricio Vieira, Janet E. Hill, Roberto Docampo

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


We report the cloning, overexpression, purification, and characterization of the Leishmania major exopolyphosphatase (LmPPX). The product of this gene (LmPPX), the first related to polyphosphate (polyP) metabolism isolated from an eukaryotic organism different from yeast, has 388 amino acids and a molecular mass of 48 kDa. LmPPX differs from other exopolyphosphatases previously investigated. Heterologous expression of LmPPX in Escherichia coli produced a functional enzyme that was similar to the yeast exopolyphosphatase with respect to its Mg2+ requirement, optimum pH, and sensitivity to cations, amino acids, and heparin but that, in contrast to the yeast enzyme and other exopolyphosphatases investigated before, acts on polyP of short chain lengths with higher rates and affinity. LmPPX is a processive enzyme, and it does not hydrolyze pyrophosphate, ATP, orp-nitrophenylphosphate. Confocal immunofluorescence microscopy using affinity-purified antibodies against the recombinant enzyme indicated an acidocalcisomal and cytosolic localization. High levels of short chain (21.4 ± 3.0 mM) and long chain polyP (55.9 ± 5.6 mM) were detected in L. major promastigotes. The unique characteristics of LmPPX and L. major polyP metabolism may facilitate the development of novel antileishmanial agents.

Original languageEnglish (US)
Pages (from-to)50899-50906
Number of pages8
JournalJournal of Biological Chemistry
Issue number52
StatePublished - Dec 27 2002
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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