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低活性形式的碳酸酐酶I。比活性很低，但经药物治疗和肾上腺切除术后活性恢复。该酶从一名患者中纯化至均匀性。该酶在抗原性和锌含量方面无法区分。另一方面，对特定抑制剂乙酰唑胺的抑制常数和结合亲和力有很大不同。巯基滴定、氨基酸分析和多肽图谱分析表明，其低活性含有混合二硫与谷胱甘肽，这与其低活性形态密切相关。这一结果支持了我们之前关于< γ > -谷氨酰环转移酶和n -乙酰己糖氨酸酶的发现，这两种酶都含有混合二硫与谷胱甘肽。蛋白质中混合二硫化物的存在似乎是一种普遍现象。

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.