Characterization of α-phosphoglucomutase isozymes from Toxoplasma gondii

Mihoko Imada, Shuichi Kawashima, Minoru Kanehisa, Tsutomu Takeuchi, Takashi Asai

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The Toxoplasma gondii genome project has revealed two putative isoforms (TgPGM-I and TgPGM-II) of α-phosphoglucomutase (EC 5.4.2.2). We obtained recombinant proteins of these isoforms from the Beverley strain of T. gondii and characterized their properties, particularly the kinetic properties of these isoforms. The specific activities of TgPGM-I and TgPGM-II for α-d-glucose 1-phosphate were 338 ± 9 and 84 ± 6 μmol/min/mg protein, respectively, at 37 °C under optimal conditions. The Kcat and Km values of TgPGM-I were 398 ± 11/s and 0.19 ± 0.03 mM and those for TgPGM-II were 93 ± 7/s and 3.53 ± 0.91 mM, respectively, for α-d-glucose 1-phosphate. Magnesium ions were the most effective divalent cations for both the enzyme activities. The maximum activities of both the enzymes were obtained in the presence of more than 0.2 mM α-d-glucose 1,6-bisphosphate. Although both enzymes were attached to the α-phosphohexomutase superfamily, amino acid sequence homology between TgPGM-I and TgPGM-II showed very low overall identity (25%). No α-phosphomannomutase (EC 5.4.2.8) activity was detected for either enzyme. The data indicated that TgPGM-I, but not TgPGM-II, may play an important role in α-d-glucose 6-phosphate production.

Original languageEnglish
Pages (from-to)206-210
Number of pages5
JournalParasitology International
Volume59
Issue number2
DOIs
Publication statusPublished - 2010 Jun 1

Keywords

  • Glycolytic pathway
  • Isozyme
  • Parafusin related protein 1
  • Toxoplasma gondii
  • α-Phosphoglucomutase

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases

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