Immunochemical studies on blood groups. XXXVI. the nature of the unsaturated residue in some oligosaccharides produced by the action of sodium hydroxide-sodium borohydride on blood-group a, b, and h substances

Abstract

Treatment of blood-group substances with sodium hydroxide-sodium borohydride gives a series of oligosaccharides, many of which are terminated by an unsaturated alditol residue, that of a 3-hexene-1,2,5,6-tetrol(R). cis-Hydroxylation of authentic samples of the trans-erythro and D- threo forms of this alditol with hydrogen peroxide and osmium tetraoxide gave the expected products, namely, DL-glucitol from the former, and D-mannitol and D-iditol from the latter. Three of the unsaturated oligosaccharides from blood-group substances, when hydroxylated under the same conditions and the product then hydrolyzed, gave mixtures of these three hexitols. The hexitols were identified by gas chromatography of their hexaacetates under conditions that permitted the separation of all six possible hexitol hexaacetates. Each oligosaccharides sample, is, therefore, a mixture of two oligosaccharides, one terminated by a trans-3-hexene- D- threo- and the other by a trans-3-hexene- erythro-tetrol residue. Periodate oxidation of the mixture of hexitol-containing disaccharides obtained by hydroxylation of β- D-GNA cp-(1→6)-R showed that the two-acetamido-2-deoxy-hexose residue is linked to C-6 of the hexenetetrol. The structures of the oligosaccharides obtained from the blood-group substances by degradation with sodium hydroxide-sodium borohydride are compared with those from hog submaxillary mucin and with those formed by the hydrolysis of blood-group substances with triethylamine.