Roles of hemoglobin allostery in hypoxia-induced metabolic alterations in erythrocytes: Simulation and its verification by metabolome analysis

Ayako Kinoshita, Kosuke Tsukada, Tomoyoshi Soga, Takako Hishiki, Yuki Ueno, Yoichi Nakayama, Masaru Tomita, Makoto Suematsu

研究成果: Article

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When erythrocytes are exposed to hypoxia, hemoglobin (Hb) stabilizes in theT-state by capturing 2,3-bisphosphoglycerate. This process could reduce the intracellular pool of glycolytic substrates, jeopardizing cellular energetics. Recent observations suggest that hypoxia-induced activation of glycolytic enzymes is correlated with their release from Band III (BIII) on the cell membrane. Based on these data, we developed a mathematical model of erythrocyte metabolism and compared hypoxia-induced differences in predicted activities of the enzymes, their products, and cellular energetics between models with and without the interaction of Hb with BIII. The models predicted that the allostery-dependent Hb interaction with BIII accelerates consumption of upstream glycolytic substrates such as glucose 6-phosphate and increases downstream products such as phosphoenolpyruvate. This prediction was consistent with metabolomic data from capillary electrophoresis mass spectrometry. The hypoxia-induced alterations in the metabolites resulted from acceleration of glycolysis, as judged by increased conversion of [13C]glucose to [13C]lactate. The allostery-dependent interaction of Hb with BIII appeared to contribute not only to maintenance of energy charge but also to further synthesis of 2,3-bisphosphoglycerate, which could help sustain stabilization of T-state Hb during hypoxia. Furthermore, such an activation of glycolysis was not observed when Hb was stabilized in R-state by treating the cells with CO. These results suggest that Hb allostery in erythrocytes serves as an O2-sensing trigger that drives glycolytic acceleration to stabilize intracellular energetics and promote the ability to release O 2 from the cells.

元の言語English
ページ(範囲)10731-10741
ページ数11
ジャーナルJournal of Biological Chemistry
282
発行部数14
DOI
出版物ステータスPublished - 2007 4 6

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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