title: Distinct substrate specificities of bacterial heparinases against N-unsubstituted glucosamine residues in heparan sulfate.
abstract: The rare N-unsubstituted glucosamine (GlcNH(3)(+)) residues in heparan sulfate have important biological and pathophysiological roles. In this study, four GlcNH(3)(+)-containing disaccharides were obtained from partially de-N-sulfated forms of heparin and the N-sulfated K5 polysaccharide by digestion with combined heparinases I, II, and III. These were identified as DeltaHexA-GlcNH(3)(+),DeltaHexA-GlcNH(3)(+)(6S),DeltaHexA(2S)-GlcNH(3)(+), and DeltaHexA(2S)-GlcNH(3)(+)(6S). Digestions with individual enzymes revealed that heparinase I did not cleave at GlcNH(3)(+) residues; however, heparinases II and III showed selective and distinct activities. Heparinase II generated DeltaHexA-GlcNH(3)(+)(6S),DeltaHexA(2S)-GlcNH(3)(+), and DeltaHexA(2S)-GlcNH(3)(+)(6S) disaccharides, whereas heparinase III yielded only the DeltaHexA-GlcNH(3)(+) unit. Thus, the action of heparinase II requires O-sulfation, whereas heparinase III acts only on the corresponding non-sulfated unit. These striking distinctions in substrate specificities of heparinases could be used to isolate oligosaccharides with novel sequences of GlcNH(3)(+) residues. Finally, heparinases were used to identify and quantify GlcNH(3)(+)-containing disaccharides in native bovine kidney and porcine intestinal mucosal heparan sulfates. The relatively high content of O-sulfated GlcNH(3)(+)-disaccharides in kidney HS raises questions about how these sequences are generated.
authors.affiliation: Cancer Research UK and the University of Manchester Department of Medical Oncology, Christie Hospital National Health Service Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wei
authors.forename: Malcolm
authors.initials: M
authors.lastname: Lyon
authors.forename: John T
authors.initials: JT
authors.lastname: Gallagher
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005417:Flavobacterium / Q000201:enzymology; D005944:Glucosamine / Q000378:metabolism*; D019763:Heparin Lyase / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism*; D011133:Polysaccharide-Lyases / Q000378:metabolism*; D013379:Substrate Specificity; D013997:Time Factors
chemical_list: D005944:Glucosamine; D019763:Heparin Lyase; D006497:Heparan Sulfate; D011133:Polysaccharide-Lyases; C114663:heparinase II; C021349:heparitinsulfate lyase