As mentioned earlier, some of the enzymes involved in early, intermediate, and late steps in the terminal glycosylation of N-linked sugar chains have been localized to one to three individual cisternae by electron microscopy using immunoperoxidase or immunogold cytochemistry (Roth and Berger, 1982; Slot and Geuze, 1983; Dunphy et al., 1985; Roth et al., 1985) .