FLUORIDE INHIBITION OF ENOLASE ACTIVITY IN-VIVO AND ITS RELATIONSHIP TO INHIBITION OF GLUCOSE-6-P FORMATION IN STREPTOCOCCUS-SALIVARIUS
FLUORIDE INHIBITION OF ENOLASE ACTIVITY IN-VIVO AND ITS RELATIONSHIP TO INHIBITION OF GLUCOSE-6-P FORMATION IN STREPTOCOCCUS-SALIVARIUS
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DOI：
10.1016/s0003-9861(71)80053-x
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发表时间：
1971-01-01
影响因子：
3.9
通讯作者：
HAMILTON, IR
中科院分区：
文献类型：
--
作者：
KANAPKA, JA;HAMILTON, IR
在NaF存在和不存在的情况下，测定了葡萄糖-6-P，2-P-甘油酸酯，P-烯醇丙酮酸酯和丙酮酸酯在唾液链球菌代谢葡萄糖的细胞中的细胞内浓度，试图阐明这种抑制剂的作用机制。添加2.4 mmNaF代谢全细胞导致葡萄糖摄取的停止和细胞葡萄糖-6-P含量的立即下降。处理和未处理细胞中2-β-甘油酸和β-烯醇丙酮酸水平的比较表明，氟化物也抑制了细胞内烯醇酶（EC 4.2.1.11）活性。这两个明显独立的氟化物效应不能分开，无论孵育介质的pH值（pH 7.2，8.0和5.8），或加入细胞的NaF浓度（最终浓度，2.4，0.36和0.12毫米）。在pH 7.2下，向代谢细胞内糖原的细胞中加入2.4 mmNaF也导致烯醇化酶活性的抑制;然而，在这种情况下，未观察到细胞葡萄糖-6-P合成的抑制。这些结果表明，氟直接参与抑制外源葡萄糖形成葡萄糖-6-P。这两个氟敏感位点之间的可能关系通过证明P-烯醇丙酮酸-磷酸转移酶系统参与葡萄糖向S.唾液证据强烈表明，烯醇化酶的氟化物抑制通过减少可用于磷酸化的β-烯醇丙酮酸的量而导致葡萄糖转运的抑制。
The intracellular concentrations of glucose-6-P, 2-P-glycerate, P-enolpyruvate, and pyruvate were determined in cells ofStreptococcus salivariusmetabolizing glucose in the presence and absence of NaF in an attempt to elucidate the mechanism of action of this inhibitor. The addition of 2.4 mmNaF to metabolizing whole cells resulted in a cessation of glucose uptake and an immediate decline in the cellular glucose-6-P content. A comparison of the 2-P-glycerate and P-enolpyruvate levels in treated and untreated cells indicated that fluoride had also inhibited intracellular enolase (EC 4.2.1.11) activity. These two apparently separate fluoride effects could not be separated regardless of the pH of the incubation medium (pH 7.2, 8.0, and 5.8), or the concentration of NaF added to the cells (final concentration, 2.4, 0.36, and 0.12 mm). The addition of 2.4 mmNaF to cells metabolizing intracellular glycogen at pH 7.2 also resulted in the inhibition of enolase activity; however, in this case, inhibition of cellular glucose-6-P synthesis was not observed. These results indicated that fluoride was directly involved in the inhibition of glucose-6-P formation from exogenous glucose. The possible relationship between the two fluoride-sensitive sites was made clear by the demonstration that the P-enolpyruvate-phosphotransferase system was involved in the transport of glucose into cells ofS. salivarius. The evidence strongly suggests that the fluoride inhibition of enolase results in the inhibition of glucose transport by reducing the amount of P-enolpyruvate available for phosphorylation.