Expression and characterization of recombinant pyruvate kinase from Toxoplasma gondii tachyzoites

Takuya Maeda, Tomoya Saito, Yoshiyo Oguchi, Miki Nakazawa, Tsutomu Takeuchi, Takashi Asai

研究成果: Article査読

22 被引用数 (Scopus)


We have cloned a cDNA encoding Toxoplasma gondii pyruvate kinase and obtained the full-length recombinant enzyme with a calculated molecular mass of 57.5 kDa. The predicted amino acid sequence of T. gondii pyruvate kinase exhibited a highest identity (63%) to that of Eimeria tenella pyruvate kinase and a lower identity of less than 25% to the pyruvate kinases from other organisms. Southern blot analysis indicated that the pyruvate kinase gene existed as a single copy in the T. gondii tachyzoite. The active recombinant enzyme contained four subunits and produced a strongly sigmoid saturation curve with phosphoenolpyruvate as the variable substrate. Fructose 1,6-diphosphate, a general activating factor of pyruvate kinase in most species, did not affect the enzyme activity. However, glucose 6-phosphate radically activated the enzyme. Fructose 2,6-diphosphate suppressed the reaction velocity at a higher concentration of phosphoenolpyruvate. These properties indicate that pyruvate kinase activity in T. gondii is regulated by unusual phosphorylated sugars.

ジャーナルParasitology Research
出版ステータスPublished - 2003 3月 1

ASJC Scopus subject areas

  • 寄生虫科
  • 獣医学一般
  • 昆虫科学
  • 感染症


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