Verhoef N J, Noordeloos P J, Leijnse B
Clin Chim Acta. 1978 Jan 2;82(1-2):45-53. doi: 10.1016/0009-8981(78)90024-4.
The enzyme heme synthetase, involved in the final step of the biosynthesis of heme, has been assessed in rat and human bone marrow and peripheral blood. The pH optimum of the enzyme in bone marrow appeared to be pH 7.6, whereas the Michaelis constant in human and rat bone marrow was found to be 1.6 micrometer and 0.6 micrometer, respectively. Rat reticulocytes showed approximately 100-times higher heme synthetase activities than did rat erythrocytes. By contrast, human reticulocytes did not show significantly higher activities than human erythrocytes. This difference between rat and human reticulocytes could be confirmed by in vitro experiments with intact cells in which iron uptake and heme synthesis of human and rat cells were compared. Finally, heme synthetase activity was assessed in bone marrow cells of two patients with sideroblastic anemia. In both cases the enzyme activities were found to be comparable to those in control bone marrow.
参与血红素生物合成最后一步的血红素合成酶，已在大鼠和人类的骨髓及外周血中进行了评估。该酶在骨髓中的最适pH值似乎为7.6，而在人类和大鼠骨髓中的米氏常数分别为1.6微摩尔和0.6微摩尔。大鼠网织红细胞的血红素合成酶活性比大鼠红细胞高约100倍。相比之下，人类网织红细胞的活性并不比人类红细胞显著更高。大鼠和人类网织红细胞之间的这种差异可以通过对完整细胞进行体外实验来证实，在该实验中比较了人类和大鼠细胞的铁摄取及血红素合成。最后，对两名铁粒幼细胞贫血患者的骨髓细胞进行了血红素合成酶活性评估。在这两个病例中，发现该酶活性与对照骨髓中的相当。
