ヒト腎細胞癌の基礎的研究 第3報: 腎細胞癌組織内にみられた新しいγ-glutamyl transpeptidaseアイソザイムについて

Abstract

Gamma-glutamyl transpeptidase (γ-GTP, E.C. 2.3.2.1) has been considered to be a member of γ-glutamyl cycle and playa physiological role in the transport of amino acids across cell membrane through this cycle. This enzyme was extracted from cancerous tissue obtained from 10 patients with renal cell carcinoma. These enzyme preparations were investigated electrophoretic ally and enzymologically in comparison with the enzyme of normal renal tissue, normal liver tissue and fetal renal tissue. The results obtained were as follows. 1) Five cancerous tissues had a novel γ-GTP which was electrophoretic ally different from that of normal kidney, fetal kidney or normal liver. Other properties of the novel γ-GTP were almost the same as that of normal kidney except molecular weight. 2) Molecular weight of the novel γ-GTP was about 130, 000, while that of normal kidney was approximately 90, 000. 3) With regard to the possible relationship between the histopathological findings of the renal cell carcinoma and the presence of the novel γ-GTP, it was revealed that the novel enzyme was detected more frequently in poorly differentiated renal cell carcinoma or in the tumor composed mainly of granular cells. Further investigation is necessary to establish the clinical significance of the novel γ-GTP, but at least it is suggested that this enzyme might be a biochemical marker of poorly differentiated renal cell carcinoma.