Infra-red Spectroscopic Evidence of Chondroitin Polysulphate and its Relation to Anticoagulant Activity

Abstract

CHONDROITIN sulphates, which are regarded as polymers composed of approximately equimolar quantities of N-acetylgalactosamine, hexuronic acid and sulphate, have been classified as chondroitin-4-sulphate (chondroitin sulphate A and B) and chondroitin-6-sulphate (chondroitin sulphate C)¹. In infra-red spectroscopic studies, evidence has been presented that chondroitin sulphates showed characteristic absorption bands at the 700–1,000 cm.⁻¹ region, which may differentiate chondroitin-4-sulphate and the 6-sulphate^2–4. A recent communication⁵ indicated that the infra-red spectra of acetylgalactosamine-4-sulphate obtained from chondroitin sulphate A and B, and of acetylgalactos-amine-6-sulphate from chondroitin sulphate of shark cartilage, corresponded respectively to those of chondroitin-4-sulphate and the 6-sulphate. Accordingly, the spectral differences would be attributed to the presence of the C₄ and C₆ sulphate in the galactosamine moieties of chondroitin sulphates. Although chondroitin sulphate from shark cartilage has the high sulphur content of 7.6 per cent (1.3 residues of sulphate per acetylgalactosamine residue), the infra-red spectra are identical to that of chondroitin C from chordoma^3,6.