Heparosan, the capsular polysaccharide of E. coli K5 is currently used as the starting material in the chemoenzymatic synthesis of heparan sulfate and the structurally related anticoagulant drug heparin. Base hydrolysis of N-acetyl groups and their subsequent N-sulfonation, are used to prepare N-sulfoheparosan an intermediate of biosynthesis. In the present study, when excess sulfonation reagent was used during N-sulfonation, some O-sulfation also took place in the N-sulfoheparosan product. After a nearly full digestion, a hexasaccharide fraction exhibited resistance to heparin lyase II. Excessive digestion by heparin lyase II and structural identification by NMR and mass spectroscopy indicated that the resistant hexasaccharide fraction has two structures, ΔUA-GlcNS-GlcA2S-GlcNS-GlcA-GlcNS and ΔUA-GlcNS-GlcA- GlcNS3S-GlcA-GlcNS in similar amounts. The 2-sulfated structure exhibited partial resistance to heparin lyase II; however the structure of ΔUA-GlcNS-GlcA-GlcNS3S was completely resistant to heparin lyase II.

Heparosan是大肠杆菌K5的荚膜多糖，目前用作化学酶法合成硫酸乙酰肝素和结构相关的抗凝药物肝素的起始材料。的碱水解ñ -乙酰基团和它们随后的Ñ -sulfonation，用于制备Ñ -sulfoheparosan中间的生物合成。在本研究中，当在N-磺化过程中使用过量的磺化试剂时，一些O-硫酸化也发生在N-磺基乙酰肝素产品。在几乎完全消化后，六糖级分表现出对肝素裂解酶 II 的抗性。肝素裂解酶 II 的过度消化和 NMR 和质谱的结构鉴定表明，抗性六糖部分具有两种结构，ΔUA-GlcNS-GlcA2S-GlcNS-GlcA-GlcNS 和 ΔUA-GlcNS-GlcA-GlcNS3S-GlcA-GlcNS，数量相似. 2-硫酸化结构对肝素裂解酶II表现出部分抗性；然而，ΔUA-GlcNS-GlcA-GlcNS3S 的结构完全耐受肝素裂解酶 II。