Strategy for the sequence analysis of heparin

The versatile biological activities of proteoglycans are mainlymediated by their glycosaminoglycan (GAG) components. Unlikeproteins and nucleic acids, no satisfactory method for sequencingGAGs has been developed. This paper describes a strategy tosequence the GAG chains of heparin. Heparin, prepared from animaltissue, and processed by proteinases and endoglucuronidases,is 90% GAG heparin and 10% peptidoglycan heparin (containingsmall remnants of core protein). Raw porcine mucosal heparinwas labelled on the amino termini of these core protein remnantswith a hydrophobic, fluorescent tag N-4-(6-dimethylamino-2-benzofuranyl)phenyl (NDBP)-isothiocyanate]. Enrichment of the NDBP-heparinusing phenyl-Sepharose chromatography, followed by treatmentwith a mixture of heparin lyase I and III, resulted in a singleNDBP-linkage region tetrasaccharide, which was characterizedas