An integrated approach using orthogonal analytical techniques to characterize heparan sulfate structure

Capillary Electrophoretic Analysis of Isolated Sulfated Polysaccharides to Characterize Pharmaceutical Products

Capillary electrophoresis is a powerful methodology for quantification and structural characterization of highly anionic polysaccharides. Separation of saccharides under conditions of electrophoretic flow, typically achieved under low pH (Ampofo et al., Anal Biochem 199: 249-255, 1991; Rhomberg et al., Proc Natl Acad Sci U S A 95: 4176-4181, 1998) is charge-based. Resolution of components is often superior to flow-based techniques, such as liquid chromatography. During the heparin contamination crisis, capillary electrophoresis was one of the key methodologies used to identify whether or not heparin lots were contaminated (Guerrini et al., Nat Biotechnol 26: 669-675, 2008; Ye et al., J Pharm Biomed Anal 85: 99-107, 2013; Volpi et al., Electrophoresis 33: 1531-1537, 2012).Here we describe a method for the isolation of sulfated heparin/heparan sulfate saccharides from urine, their digestion by deployment of heparinase enzymes (Ernst et al., Crit Rev Biochem Mol Biol 30: 387-444, 1995) resolution of species through use of orthogonal digestions, and analysis of the resulting disaccharides by capillary electrophoresis.

Analysis of the Glycosaminoglycan Chains of Proteoglycans

Glycosaminoglycans (GAGs) are heterogeneous, negatively charged, macromolecules that are found in animal tissues. Based on the form of component sugar, GAGs have been categorized into four different families: heparin/heparan sulfate, chondroitin/dermatan sulfate, keratan sulfate, and hyaluronan. GAGs engage in biological pathway regulation through their interaction with protein ligands. Detailed structural information on GAG chains is required to further understanding of GAG-ligand interactions. However, polysaccharide sequencing has lagged behind protein and DNA sequencing due to the non-template-driven biosynthesis of glycans. In this review, we summarize recent progress in the analysis of GAG chains, specifically focusing on techniques related to mass spectroscopy (MS), including separation techniques coupled to MS, tandem MS, and bioinformatics software for MS spectrum interpretation. Progress in the use of other structural analysis tools, such as nuclear magnetic resonance (NMR) and hyphenated techniques, is included to provide a comprehensive perspective.

Heparan Sulfate Identification and Characterisation: Method II. Enzymatic Depolymerisation and SAX-HPLC Analysis to Determine Disaccharide Composition

Heparan sulfate (HS) is purified from complex matrices and often not fully characterised to validate its assignment. The characterisation of heparins and heparan sulfates through enzymatic depolymerisation and subsequent strong anion-exchange high performance liquid chromatography (SAX-HPLC) analysis and quantitation of the resulting disaccharides is a critical tool for assessing the structural composition of this class of compound. This protocol details a methodology to reproducibly determine the disaccharide composition of heparan sulfate by enzymatic depolymerisation and SAX-HPLC analysis. A complementary method for identification and characterisation of heparan sulfate can be found at Carnachan and Hinkley (2017).