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

在细胞质中发现了几种中性的α-甘露糖苷酶。经Co(II)活化后的甘露糖苷酶具有独特的底物特异性。然而，目前唯一纯化的酶是鹌鹑输卵管中的酶，其作用和激活机制尚不清楚。用天然和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法从鸡输卵管中纯化了Co(II)激活的α-甘露糖苷酶，并用吡啶糖链分析了其底物的特异性。甘露糖苷酶属于胞浆组分中的中性α-甘露糖苷酶。结果表明，鸡输卵管α-甘露糖苷酶的底物专一性和Co(II)的激活作用与鹌鹑输卵管的相同。通过对最适激活pH、最适Co(II)浓度、几种多肽、酶抑制剂的分析表明，该甘露糖苷酶含有蛋白酶。然而，激活的甘露糖苷酶与未激活的甘露糖苷酶显示出几乎相同的电泳图谱。需要进一步分析该酶的结构才能阐明其确切的作用机制。

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.