Hirsch R E, Lin M J, Pulakhandam U R, Nagel R L, Sandberg S
Department of Medicine, Albert Einstein College of Medicine, Bronx, NY.
Photochem Photobiol. 1993 May;57(5):885-8. doi: 10.1111/j.1751-1097.1993.tb09229.x.
Whole blood and hemolysates from seven normal and three erythropoietic protoporphyria patients were compared in terms of their hemoglobin function. The oxygen affinity (P50) of the erythropoietic protoporphyria hemolysates compared to normals (13.1 +/- 0.2 vs 17.5 +/- 0.3 mmHg; P < 0.001) and erythropoietic protoporphyria erythrocytes compared to normals (23.4 +/- 0.6 vs 27.1 +/- 0.5 mmHg; P < 0.001) were increased while oxygen-binding cooperativity (n-value of the Hill equation) were similar. We conclude that hemoglobin function in erythropoietic protoporphyria patients is altered, but without pathophysiologic consequences. Because hemoglobin in which protoporphyrin IX substitutes for heme has a low oxygen affinity, our findings of a higher than normal affinity in erythropoietic protoporphyria red cells and hemolysates may indirectly support the findings by others that protoporphyrin IX binds to hemoglobin at non-heme-binding sites. In addition, based on the effect of other abnormal hemoglobins, this shift in P50 will decrease any tendency for anemia in erythropoietic protoporphyria patients.
对7名正常人和3名红细胞生成性原卟啉症患者的全血和溶血产物的血红蛋白功能进行了比较。与正常人相比，红细胞生成性原卟啉症溶血产物的氧亲和力（P50）升高（分别为13.1±0.2 mmHg和17.5±0.3 mmHg；P<0.001），与正常人相比，红细胞生成性原卟啉症红细胞的氧亲和力也升高（分别为23.4±0.6 mmHg和27.1±0.5 mmHg；P<0.001），而氧结合协同性（希尔方程的n值）相似。我们得出结论，红细胞生成性原卟啉症患者的血红蛋白功能发生了改变，但没有病理生理后果。由于用原卟啉IX替代血红素的血红蛋白具有低氧亲和力，我们在红细胞生成性原卟啉症红细胞和溶血产物中发现的高于正常的亲和力可能间接支持了其他人的发现，即原卟啉IX在非血红素结合位点与血红蛋白结合。此外，基于其他异常血红蛋白的作用，P50的这种变化将降低红细胞生成性原卟啉症患者发生贫血的任何倾向。
