Biosynthesis and processing of Spodoptera frugiperda alpha-mannosidase III.

We previously cloned a lepidopteran insect cell cDNA that encodes a class II alpha-mannosidase that is localized in the Golgi apparatus but is cobalt-dependent, has a neutral pH optimum, hydrolyzes Man(5)GlcNAc(2) to Man(3)GlcNAc(2), and cannot hydrolyze GlcNAcMan(5)GlcNAc(2). This enzyme was designated SfManIII to distinguish it from Golgi alpha-mannosidase II and indicate its derivation from the fall armyworm Spodoptera frugiperda. In the present study, we prepared a polyclonal antibody and used it to study the biosynthesis and processing of SfManIII.