Kark J A, Tarassoff P G, Bongiovanni R
J Clin Invest. 1983 May;71(5):1224-9. doi: 10.1172/jci110871.
Although pyridoxal phosphate is known to inhibit gelation of purified hemoglobin S, antisickling activity has never been demonstrated for intact erythrocytes. We incubated washed erythrocytes at 37 degrees C either in buffer alone, or with added pyridoxal phosphate or pyridoxal, washed these cells, suspended them in untreated buffer, and compared the percent modified hemoglobin, the oxygen affinity, and the extent of sickling under hypoxia. Pyridoxal phosphate modified intracellular hemoglobin more slowly than pyridoxal. Pyridoxal phosphate lowered the oxygen affinity of normal cells, but had no effect on oxygen binding by sickle cells. Pyridoxal increased the oxygen affinity of normal and sickle erythrocytes equally. Pyridoxal phosphate significantly inhibited sickling of sickle or sickle trait erythrocytes (P less than 0.001). Inhibition of sickling by pyridoxal phosphate was largely independent of oxygen binding; whereas inhibition of sickling by pyridoxal was almost entirely dependent on increased oxygen binding. Although pyridoxal phosphate and pyridoxal both inhibit sickling by modification of hemoglobin S, they differ in the kinetics of whole cell modification, the effect on oxygen affinity of intact cells, and the mechanism of action of the antisickling activity.
尽管已知磷酸吡哆醛可抑制纯化的血红蛋白S凝胶化，但完整红细胞的抗镰状化活性从未得到证实。我们将洗涤后的红细胞在37℃下分别于单独的缓冲液中、添加了磷酸吡哆醛或吡哆醛的缓冲液中孵育，洗涤这些细胞，将它们悬浮在未处理的缓冲液中，并比较修饰血红蛋白的百分比、氧亲和力以及低氧条件下的镰状化程度。磷酸吡哆醛修饰细胞内血红蛋白的速度比吡哆醛慢。磷酸吡哆醛降低了正常细胞的氧亲和力，但对镰状细胞的氧结合没有影响。吡哆醛同等程度地增加了正常和镰状红细胞的氧亲和力。磷酸吡哆醛显著抑制镰状或镰状性状红细胞的镰状化（P小于0.001）。磷酸吡哆醛对镰状化的抑制在很大程度上与氧结合无关；而吡哆醛对镰状化的抑制几乎完全依赖于氧结合的增加。尽管磷酸吡哆醛和吡哆醛都通过修饰血红蛋白S来抑制镰状化，但它们在全细胞修饰动力学、对完整细胞氧亲和力的影响以及抗镰状化活性的作用机制方面存在差异。
