Maeda N, Takahashi K, Aono K, Shiga T
Br J Haematol. 1976 Nov;34(3):501-9. doi: 10.1111/j.1365-2141.1976.tb03596.x.
Pyridoxal 5'-phosphate (PLP), an allosteric effector for the oxygenation of haemoglobin, was incorporated readily into erythrocytes and disappeared from them by simple passive diffusion. The disappearance of PLP from the cells was accelerated by the generation of 2,3-DPG in a medium of inosine, pyruvate and phosphate. The oxygen dissociation curve measured at an extracellular pH of 7.4 demonstrated that PLP incorporated into the cells also lowered the oxygen affinity and that PLP functionally compensated for a metabolically reduced 2,3-DPG. However, the dependency of the oxygen affinity on the intracellular PLP concentration showed a different pattern from the observed for 2,3-DPG. On the other hand, the lowering of intracellular pH by organic phosphates accumulated in the cells was much larger with PLP than with 2,3-DPG. The peculiar relationship between the oxygen affinity of erythrocytes and the intracellular PLP concentration is discussed in detail. The present study may offer a new prospect for the preservation of blood with a normal function.
磷酸吡哆醛（PLP）是血红蛋白氧合的变构效应剂，它很容易进入红细胞，并通过简单的被动扩散从红细胞中消失。在含有肌苷、丙酮酸和磷酸盐的培养基中，2,3-二磷酸甘油酸（2,3-DPG）的生成加速了PLP从细胞中的消失。在细胞外pH值为7.4时测得的氧解离曲线表明，进入细胞的PLP也降低了氧亲和力，并且PLP在功能上补偿了代谢性降低的2,3-DPG。然而，氧亲和力对细胞内PLP浓度的依赖性表现出与2,3-DPG不同的模式。另一方面，细胞内积累的有机磷酸盐使细胞内pH值降低，PLP的作用比2,3-DPG大得多。详细讨论了红细胞氧亲和力与细胞内PLP浓度之间的特殊关系。本研究可能为保存具有正常功能的血液提供新的前景。
