The conformation of some pyranose moieties in the molecules of α- -hexopyranose-1-phosphates, purine and pyrimidine 5′-(α- -pyranosyl pyrophosphates), and mucopolysaccharides

Abstract

Purified porcine heparin was hydrolyzed with 0.5m hydrochloric acid for 20 h at 80°. The neutralized hydrolyzate was subjected to gel filtration through Sephadex G-10. Fractions containing products of higher molecular weight than disaccharide were treated repeatedly by the foregoing procedure. The disaccharide-containing fractions thus obtained were purified by preparative, high-voltage paper electrophoresis at pH 1.9, two disaccharides were then separated by multiple, preparative paper-chromatography. The yields or the disaccharides (P-4 and P-5) were 13.1 and 3.8 mg, respectively, in terms of D-glucuronic acid, from 300 mg of the starting heparin. As P-4 was not homogeneous, it was further purified by preparative, high-voltage paper electrophoresis at pH 2.7. Analytical data of P-4 and P-5 of their N-acetyl derivatives (P-4A and P-5A) before and after reduction with sodium borohydride indicated that P-4 and P-5 consisted of equimolar amounts 2-amino-2-deoxy-D-glucose and hexuronic acid, having hexuronic acid at the reducing end. The hexuronic acid in P-4A and P-5A was determined by g.l.c. to be L-iduronic acid and D-glucuronic acid, respectively. After reduction of the products obtained by Smith degradation of the reduce P-4A and P-5A, threitol and erythritol, respectively, and also glycerol were detected by g.l.c. The α-anomeric configuration of the 2-acetamido-2-deoxy-D-glucopyranosyl linkages of P-4A and P-5A was suggested by i r. and p.m.r. spectra and by the high dextrorotations; ( values of P-4A and P-5A were +91.6° (in water) and + 114.9° (in water), respectively. The foregoing observations indicated that P-4 and P-5 were O-(2-amino-2-deoxy-α-D-glucopyranosyl-(1→4)-L-idopyranuronic acid and O-(2-amino-2-deoxy-α-D-glucopyranosyl)-(1→4)-D-glucopyranuronic acid, respectively.