NEURAMIN-LACTOSE NEURAMIN-LACTOSE SULFATE AND LACTOSE SULFATE FROM RAT MAMMARY GLANDS . ISOLATION PURIFICATION AND PERMETHYLATION STUDIES

A method for the isolation of acidic oligosaccharides from rat mammary gland extracts has been developed. This method involves fractionation of the extract on a column of Dowex 1-X8 formate which was eluted with a gradient of pyridinium formate. Six peaks were obtained containing neuramin-lactose, neuramin- lactose sulfate, lactose sulfate, N-acetylneuraminic acid (absent in fresh tissue), and two unidentified acidic sugars, respectively. After purification by gel filtration on Sephadex G-15, neuramin-lactose, neuramin-lactose sulfate, and lactose sulfate were subjected to permethylation with methylsulfinyl carbanion and methyl iodide in dimethyl sulfoxide solution. From the results obtained in the studies of these methylated sugars, the following structures were established: neuramin-lactose, O-α- D-N-acetylneurammyl-(2→3)-O-β-D-galactopyranosyl- (1→4)-D-glucopyranose; neuramin-lactose sulfate, O- α-D-N-acetylneuraminyl-(2→3)-O-β-D-galactopyranosyl 6-O-sulfate-(1→4)-D-glucopyranose; and lactose sulfate, O-β-D-galactopyranosyl 6-O-sulfate-(1→4)-D-glucopy-ranose. © 1968, American Chemical Society. All rights reserved.