Clinical and Basic Study on Human Erythrocyte Carbonic Anhydrase I-Presence of a Mixed Disulfide with Glutathione.

在5例原发性醛固酮增多症患者的红细胞中发现了一种活性较低的碳酸氢酶I。酶的比活力很低，但通过药物治疗和肾上腺切除术可以恢复活力。从其中一名患者身上提取的酶纯化为均一。就其抗原性和锌含量而言，该酶是无法区分的。另一方面，对一种特定的抑制剂乙酰唑胺的抑制常数和结合亲和力有很大的不同。巯基滴定、氨基酸分析和肽谱分析表明，活性较低的Fin含有二硫键和谷胱甘肽的混合形式，这与其低活性形式密切相关。这一结果支持我们之前关于谷氨酰环转移酶和N-乙酰氨基己糖苷酶的发现，这两种酶都被发现含有二硫键和谷胱甘肽的混合结构。蛋白质中混合二硫键的存在似乎是一种常见的现象。

A low activity form of carbonic anhydrase I was found in erythrocytes of five patients with primary aldosteronism. The specific activity was very low, however the activity was restored by drug treatment as well as adrenalectomy.The enzyme was purified to homogeneity from one of the patients. The enzyme was not distinguishable with respect to its antigenecity and zinc content. On theother hand, the inhibition constant and binding affinity to a specific inhibito, acetazolamide, was quite different. Sulfhydryl titration, amino acid analysis and peptide mapping analysis suggested that the low activity from contains a mixed disulfide with glutathione which is closely associated with its low activity form. This result supports our previous findings on <gamma> -glutamyl cyclotransferase and N-acetyl hexosaminidase, both of which were found to contain a mixed disulfide with glutathione. The presence of a mixed disulfide in the protein seems to be a common phenomenon.