Neutral core oligosaccharides of bovine submaxillary mucin - Use of lead tetraacetate in the cold for establishing branch positions

Oligosaccharide alditols were released from bovine submaxillary mucin by al kaline borohydride treatment. The fractions containing smaller neutral olig osaccharides were separated by HPLC, to give, in the mono-, di- and trisacc haride-alditol sizes, 19 different structures, in addition to three fucosyl ated tetrasaccharide alditols. Molecules were identified by NMR spectroscop y, electrospray-mass-spectrometry - mass-spectrometry, permethylation analy ses, and highly selective Pb(OAc)(4) oxidation at -30 degrees C, followed b y borohydride reduction. Pb(OAc), oxidation was found to be generally appli cable in identifying the branch position(s) of substitutions for all core s tructures. Among the isolated oligosaccharide alditols were structures not previously reported, including 12 structures not reported from bovine subma xillary mucin, and four structures (three core structures) not found in the Carbbank database.