Analysis of activation of neutral alpha-mannosidase activated with Co(II)

在细胞胞浆中发现了几种中性α -甘露糖苷酶。甘露糖酶在被Co（II）激活后具有独特的底物特异性。然而，唯一纯化的酶是鹌鹑的输卵管，酶的作用和激活机制尚不清楚。用Co（II）活化的α -甘露糖苷酶从母鸡的输卵管中纯化出来，通过原生和SDS PAGE判断其均匀性。用吡啶层压糖链分析了其底物特异性。甘露糖苷酶在胞浆中属于中性α -甘露糖苷酶。结果表明，鸡输卵管中α -甘露糖苷酶的底物特异性和Co（II）活化作用与鹌鹑输卵管相同。最佳活化pH、Co（II）的最佳浓度、蛋白酶活性分析（与多肽、蛋白酶抑制剂分析）表明甘露糖苷酶含有蛋白酶。然而，活化的甘露糖苷酶与未活化的甘露糖苷酶的电泳模式几乎相同。需要进一步分析酶的结构来阐明确切的机制。

Several neutral alpha-mannosidases were reported in cytosol of cells. The mannosidases have unique substrate specificities after activation with Co(II). Howevere the only Purified enzyme was of quail oviduct, and the role of the enzyme and activation mechanism were unknown.alpha-Mannosidase activated with Co(II) was purified from hen oviduct to homogeneity as judged by native and SDS PAGE.Its substrate specificity was analyzed by using pyridylaminated sugar chains. The mannosidase was found to belong to the neutral alpha-mannosidase in cytosol fraction. The results show that substrate specificities and activation with Co(II) of the alpha-mannosidase from hen oviduct were the same as those of quail oviduct. Analysis of the optimal activation pH,optimal concentration of Co(II), protease activity by analysis with several peptides, proteinase inhibitors indicate that the mannosidase contains protease. However, the activated mannosidase showed almost the same electrophoretic patterns as compared with the one without activation. Further analysis of the structure of the enzyme is needed to clarify the exact mechanism.