N.m.r. studies of oligosaccharides obtained by degradation of bovine lung heparin with nitrous acid.

The oligosaccharides IdoA(2SO3)-[GlcNSO3(6SO3)-IdoA(2SO3) ]n-anManOH(6SO3) (n = 1-4) have been prepared from bovine lung heparin by treatment with nitrous acid followed by borohydride reduction and then fractionation by gel filtration. The major resonances of the 1H- (400 MHz) and 13C-n.m.r. (100 MHz) spectra for each oligosaccharide fraction have been assigned using two-dimensional COSY, NOESY, and 13C-1H correlation experiments. The 1H resonances, representing the three distinct molecular environments of IdoA(2SO3), namely, at the non-reducing terminus, adjacent to the reducing terminal anManOH(6SO3), and in the [GlcNSO3(6SO3)-IdoA(2SO3)] repeat sequence, have been assigned.