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

在细胞的胞质溶胶中报道了几种中性α-甘露糖苷酶。甘露聚糖酶在用Co（II）活化后具有独特的底物特异性。从鸡输卵管中分离纯化了Co（Ⅱ）活化的α-甘露糖苷酶，经SDS PAGE和非变性PAGE鉴定，酶的底物特异性为吡啶胺化糖链。甘露糖苷酶在胞质中属于中性α-甘露糖苷酶。结果表明，鸡输卵管α-甘露糖苷酶的底物特异性和Co（II）激活作用与鹌鹑输卵管相同。通过对最适活化pH、最适Co（II）浓度、蛋白酶活性和几种多肽、蛋白酶抑制剂的分析，表明甘露糖苷酶中含有蛋白酶。然而，与未活化的甘露糖苷酶相比，活化的甘露糖苷酶显示出几乎相同的电泳图谱。需要对酶的结构进行进一步分析以阐明确切的机制。

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.