Chemical structure of epiglycanin, the major glycoprotein of the TA3-Ha ascites cell. The carbohydrate chains.

The reduced oligosaccharide chains of epiglycanin, the major cell-surface glycoprotein of the TA3-Ha ascites tumor cell of the strain A mouse were cleaved by a fi elimination reaction under reductive conditions. Neutral and acidic oligosaccharides were separated on a column of Dowex 1 (formate). The neutral reduced oligosaccharides, upon gel filtration on Bio-Gel P-2, yielded three fractions, which were identified as a reduced monosaccharide (N3), a reduced disaccharide (Nz), and a reduced tetrasaccharide (N,). Similarly, the reduced acidic oligosaccharides were separated into a trisaccharide (Az) and a hexasaccharide (A,). Permethylation of each oligosaccharide, followed by mass spectroscopy of the alditol acetate derivatives and periodate oxidation, established the linkages in Nz, AI, and AZ. Cleavage by specific glycosylhydrolases, in addition to periodate oxidation gave the sequence of residues in AI. The reduced chains were identified as: Ns, 2-acetamido-2-deoxy-D-galactitol; Nz, 2-acetamido-2-deoxy-30-/I-D-galactopyranosyl-D-galactitol; Az, O-(N-acetylcu-neuraminosyl)-(2 += 3)-0-P-n-galactopyranosyl-(1 + 3)-2-acetamido-2-deoxy-D-galactitol; AI, O-(N-acetyl-aneuraminosyl)-(2 + 3)-~-D-galactopyranosyl-(l --+ 4)-O2-acetamido-2-deoxy-P-D-glucopyranosyl-(1 + 3)-O-p-