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首页> 外文期刊>Journal of bacteriology >Use of 31P nuclear magnetic resonance spectroscopy and 14C fluorography in studies of glycolysis and regulation of pyruvate kinase in Streptococcus lactis.
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Use of 31P nuclear magnetic resonance spectroscopy and 14C fluorography in studies of glycolysis and regulation of pyruvate kinase in Streptococcus lactis.

机译：31P核磁共振波谱法和14C荧光照相法在研究乳酸链球菌中的糖酵解和丙酮酸激酶调节中的应用。

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High-resolution 31P nuclear magnetic resonance spectroscopy and 14C fluorography have been used to identify and quantitate intermediates of the Embden-Meyerhof pathway in intact cells and cell extracts of Streptococcus lactis. Glycolysing cells contained high levels of fructose 1,6-bisphosphate (a positive effector of pyruvate kinase) but comparatively low concentrations of other glycolytic metabolites. By contrast, starved organisms contained only high levels of 3-phosphoglycerate, 2-phosphoglycerate, and phosphoenolpyruvate. The concentration of Pi (a negative effector of pyruvate kinase) in starved cells was fourfold greater than that maintained by glycolysing cells. The following result suggest that retention of the phosphoenolpyruvate pool by starved cells is a consequence of Pi-mediated inhibition of pyruvate kinase: the increase in the phosphoenolpyruvate pool (and Pi) preceded depletion of fructose 1,6-bisphosphate, and reduction in intracellular Pi (by a maltose-plus-arginine phosphate trap) caused the restoration of pyruvate kinase activity in starved cells. Time course studies showed that Pi was conserved by formation of fructose 1,6-bisphosphate during glycolysis. Conversely, during starvation high levels of Pi were generated concomitant with depletion of intracellular fructose 1,6-bisphosphate. The concentrations of Pi and fructose 1,6-bisphosphate present in starved and glycolysing cells of S. lactis varied inversely. The activity of pyruvate kinase in the growing cell may be modulated by the relative concentrations of the two antagonistic effectors.
机译：高分辨率31P核磁共振波谱和14C荧光照相法已被用于鉴定和定量乳酸链球菌完整细胞和细胞提取物中Embden-Meyerhof途径的中间体。糖酵解细胞含有高水平的果糖1,6-二磷酸（丙酮酸激酶的阳性效应物），但其他糖酵解代谢物的浓度相对较低。相比之下，饥饿的生物仅含有高水平的3-磷酸甘油酸酯，2-磷酸甘油酸酯和磷酸烯醇丙酮酸。饥饿细胞中Pi（丙酮酸激酶的负效应子）的浓度比糖酵解细胞维持的浓度高四倍。以下结果表明饥饿的细胞对磷酸烯醇丙酮酸池的保留是Pi介导的丙酮酸激酶抑制作用的结果：磷酸烯醇丙酮酸池（和Pi）的增加先于果糖1,6-二磷酸耗尽，而细胞内Pi减少（通过麦芽糖加精氨酸磷酸盐阱）引起饥饿细胞中丙酮酸激酶活性的恢复。时程研究表明，糖酵解过程中果糖1,6-双磷酸酯的形成可保护Pi。相反，在饥饿期间，伴随着细胞内果糖1,6-二磷酸的消耗而产生高水平的Pi。乳酸链球菌饥饿和糖酵解细胞中的Pi和果糖1,6-二磷酸酯的浓度成反比。丙酮酸激酶在生长细胞中的活性可以通过两种拮抗物的相对浓度来调节。

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