Takeda E, Kuroda Y, Toshima K, Naito E, Ito M, Miyao M, Kominami E, Katunuma N
Clin Chim Acta. 1986 Mar 16;155(2):109-15. doi: 10.1016/0009-8981(86)90271-8.
The activities of Z-Phe-Arg-NMec(ZPA) hydrolase, cathepsin B and cathepsin H and the concentration of endogenous thiol protease inhibitor in fibroblasts from patients with galactosialidosis were found not to be significantly different from those in control fibroblasts. Culture for 5 days with thiol protease inhibitors such as leupeptin, E-64 or Z-Phe-Phe-CHN2 partially restored the beta-galactosidase activity of fibroblasts from patients, but did not affect the beta-galactosidase activity of fibroblasts from control subjects. However, culture with leupeptin, but not other protease inhibitors, increased the ZPA hydrolase and cathepsin B activities of fibroblasts from both patients and controls 2- to 4-fold. Sephadex G-75 chromatography showed that the activity of high molecular weight ZPA hydrolase, which was initially predominant in fibroblasts, decreased markedly during their culture with leupeptin, while the activities of lower molecular weight ZPA hydrolase and cathepsin B increased about 5-fold. These results suggest that high molecular weight ZPA hydrolase, which is presumably cathepsin J, degrades beta-galactosidase, and that the defect in galactosialidosis is impaired protection of beta-galactosidase from degradation.
结果发现，半乳糖唾液酸贮积症患者成纤维细胞中的Z-苯丙氨酰-精氨酸-甲基香豆素酰胺（ZPA）水解酶、组织蛋白酶B和组织蛋白酶H的活性以及内源性巯基蛋白酶抑制剂的浓度与对照成纤维细胞中的这些指标并无显著差异。用亮肽素、E-64或Z-苯丙氨酰-苯丙氨酸-重氮甲烷等巯基蛋白酶抑制剂培养5天，可部分恢复患者成纤维细胞的β-半乳糖苷酶活性，但对对照受试者成纤维细胞的β-半乳糖苷酶活性没有影响。然而，用亮肽素培养（而非其他蛋白酶抑制剂）可使患者和对照的成纤维细胞的ZPA水解酶和组织蛋白酶B活性提高2至4倍。葡聚糖G-75层析显示，成纤维细胞中最初占主导地位的高分子量ZPA水解酶在与亮肽素共同培养期间活性显著降低，而低分子量ZPA水解酶和组织蛋白酶B的活性增加了约5倍。这些结果表明，推测为组织蛋白酶J的高分子量ZPA水解酶可降解β-半乳糖苷酶，且半乳糖唾液酸贮积症的缺陷在于β-半乳糖苷酶免受降解的保护作用受损。
