Forsee W T, Schutzbach J S
J Biol Chem. 1981 Jul 10;256(13):6577-82.
An alpha-mannosidase specific for the hydrolysis of alpha-1,2-mannosyl-mannose linkages has been solubilized and partially purified from rabbit liver microsomes. The enzyme is inhibited by EDTA and has optimal activity in the presence of calcium ions. The purified enzyme has a requirement for nonionic detergents or for specific phospholipids. At detergent concentrations appreciably below the critical micelle concentration, the enzyme is active in the presence of phosphatidylcholine or phosphatidylethanolamine but not with phosphatidylinositol, phosphatidylglycerol, or phosphatidic acid. At concentrations of phosphatidylcholine which provide optimal activity, the enzyme is strongly inhibited by phosphatidylinositol or phosphatidylglycerol. The substrate specificity of the alpha-mannosidase toward oligosaccharide substrates suggests that the enzyme may be involved in the processing of the oligosaccharide chains of mammalian glycoproteins.
一种特异性水解α-1,2-甘露糖基-甘露糖键的α-甘露糖苷酶已从兔肝微粒体中溶解并部分纯化。该酶受EDTA抑制，在钙离子存在下具有最佳活性。纯化后的酶需要非离子型去污剂或特定的磷脂。在去污剂浓度明显低于临界胶束浓度时，该酶在磷脂酰胆碱或磷脂酰乙醇胺存在下具有活性，但在磷脂酰肌醇、磷脂酰甘油或磷脂酸存在下无活性。在提供最佳活性的磷脂酰胆碱浓度下，该酶受到磷脂酰肌醇或磷脂酰甘油的强烈抑制。α-甘露糖苷酶对寡糖底物的底物特异性表明，该酶可能参与哺乳动物糖蛋白寡糖链的加工过程。
