FIGURE 4.

Several fOSs are further modified by Golgi-resident mannosyltransferase, Och1p. A, the structure of the N-linked glycan chain in S. cerevisiae. The mannose residue added by Och1p is marked by an asterisk. B–E, unassigned peaks (c3, d2, e1, and f1) were digested with α-1,2-mannosidase alone or with both α-1,2-mannosidase and α-1,6-mannosidase. M5–M9 in the size fractionation HPLC charts represent elution positions of authentic standards of M5GN2-PA-M9GN2-PA. The elution positions of the authentic standards (M8H, M8I, and M8J) are indicated by closed arrowheads (C and D, lower chart).