Structure elucidation of a novel acidic tetrasaccharide and hexasaccharide derived from a chemically modified heparin

Abstract

In the course of development of potentially more bioactive forms of heparin’ for use as an anticoagulant, we had occasion to prepare a modified heparin first reported by Jaseja et al.‘. Treatment of unfractionated bovine lung heparin with an alkaline solution at high temperature (105-110°C) for 24 h, according to method developed by Rej and Perlin3, results in a modified heparin. To structurally characterize the sample of modified heparin, it was depolymerized with heparinase (heparin lyase I, EC 4.2.2.7). This resulted in the isolation of the hitherto unreported tetrasaccharide and hexasaccharide. This note describes the isolation and structure elucidation of two novel oligosaccharides. The solution conformation of these oligosaccharides may aid in developing a better understanding of the conformational preferences of the uranic acid residues. Treatment of heparin with a sodium carbonate solution according to the method developed by Perlin and co-workers2$ results in a modified heparin. However, because heparin is a polydisperse microheterogeneous mixture, the modified heparin is also a mixture, and thus its precise structure was ill-defined. The ‘H NMR spectrum of the intact modified polymer indicated the presence of