220 MHz spectra of heparin, chondroitins, and other mucopolysaccharides

Characteristics of proton magnetic resonance spectra of heparins at 220 MHz, coupled with spectral data for model compounds and with information obtained chemically, indicate that heparins are composed principally of (1 → 4)-linked α-L-idopyranosyluronic acid residues (3) and 2-amino-2-deoxy-α-D-glucopyranosyl residues (1); also, that sulfate groups are located at position -2 and -6 of 1, and -2 of 3. D-Glucopyranosyluronic acid residues (2) appear to be minor constituents, which is at variance with all structures that have been proposed previously for heparin.Spectra of chondroitins A, B, and C, which are readily distinguishable, are in close accord with formulae that have been proposed for these mucopolysaccharides; on the same basis, the spectrum of keratan sulfate is less consistent. Hyaluronic acid affords a poorly resolved though, nonetheless, distinctive spectrum. The general view that mucopolysaccharides are constituted basically of residues of hexosamine and uronic acid in equimolar proportion receives support from the current findings. However, heparitin appears to possess a more heterogeneous type of structure than do these other polymers.