Separation of hydroxyl protected heparin derived disaccharides using reversed-phase high-performance liquid chromatography

Recent Liquid Chromatographic Approaches and Developments for the Separation and Purification of Carbohydrates

Carbohydate purification remains a bottleneck in securing analytical standards from natural sources or by chemical or enzymatic synthesis. This review highlights the scope and remaining limitations of recent approaches and methods development in liquid chromatography for robust and higher-throughput carbohydrate separation and isolation.

Protocol for the purification of protected carbohydrates: toward coupling automated synthesis to alternate-pump recycling high-performance liquid chromatography

Given recent advances in automated oligosaccharide synthesis, analytical techniques that can be coupled to a synthetic framework are needed to not just identify but also purify to homogeneity protected carbohydrate compounds at levels of ≥99.5% purity. Herein, an alternate-pump recycling high-performance liquid chromatography (R-HPLC) method has been developed to allow purification of protected carbohydrates at levels of ≥99.5% purity.

Towards the chemoenzymatic synthesis of heparan sulfate oligosaccharides: Oxidative cleavage of p-nitrophenyl group with ceric ammonium salts

We have developed an efficient chemoenzymatic synthesis of heparan sulfate oligosaccharides employing the para-nitrophenyl (p-NP) β-glucuronide as an acceptor compatible with enzymatic elongation and one that significantly simplifies oligosaccharide purification on C-18 resin. Employing ceric ammonium nitrate as oxidative reagent to remove the p-NP group unexpectedly also removed the glucuronic acid residue at the reducing-end, affording a smaller oligosaccharide. The application of ceric ammonium sulfate allowed the removal of the p-NP without concomitant loss of the adjacent glucuronic acid offering a route to longer heparin sulfate oligosaccharide products.

Compositional profiling of heparin/heparan sulfate using mass spectrometry: assay for specificity of a novel extracellular human endosulfatase

An important class of carbohydrates studied within the field of glycobiology, heparin and heparan sulfate (HS) have been implicated in a diverse array of biological functions. Changes in their sulfation pattern and domain organization have been associated with different pathological situations such as viral infectivity, tumor growth, and metastasis. To obtain structural information about these biomolecules, and the modifications they may undergo during different stages of cell growth and development, a mass spectrometry-based method was developed and used to obtain unambiguous structural information on the glycosaminoglycans (GAGs) that comprise heparin/HS. The method was applied to assay for the heparin substrate specificity of a newly discovered human extracellular endosulfatase, HSulf-2, which has been implicated in tumorigenesis. This new protocol incorporates 12 known heparin disaccharides, including three sets of isomers. A unique response factor (R) is determined for each disaccharide, whereas a multiplexed and data processing method is incorporated for faster data acquisition and quantification purposes. Proof of principle was performed by using various heparin/HS samples isolated from bovine and porcine tissues.

Compositional analysis and quantification of heparin and heparan sulfate by electrospray ionization ion trap mass spectrometry

A new method using a combination of electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MSn) was developed for the identification and quantitative analysis of eight heparan sulfate (HS)- and heparin-derived delta-disaccharides obtained by enzymatic depolymerization. The compositional analysis of nonisomeric disaccharide constituents of heparin/HS was achieved from full-scan MS1 spectra using an internal standard and a calculated response factor for each disaccharide. Diagnostic product ions from MSn spectra of isomeric disaccharides were used for the quantitative analysis of the relative amounts of each of the isomers in mixtures. The protocol was validated using several quality control samples and showed satisfactory accuracy and precision. The analysis is rapid, accurate, and uses no purification or separation steps prior to analysis by MS, thus reducing sample consumption and analysis time of traditional methods. Using this quantitative analysis procedure, percentages of disaccharide compositions for heparins from porcine and bovine intestinal mucosa and heparan sulfate from bovine kidney were determined.