heparitin-sulfate and 2-aminoacridone

Glycosaminoglycans are a heterogeneous family of linear polysaccharides comprised of repeating disaccharide subunits that mediate many effects at the cellular level. There is increasing evidence that the nature of these effects is determined by differences in disaccharide composition. However, the determination of GAG disaccharide composition in biological samples remains challenging and time-consuming. We have developed a method that uses derivatization and selected ion recording and RP-UPLCMS resulting in rapid separation and quantification of twelve heparin/heparin sulfate disaccharides from 5 μg GAG. Limits of detection and quantitation were 0.02-0.15 and 0.07-0.31 μg/ml respectively. We have applied this method to the novel analysis of disaccharide levels extracted from heparan sulfate and human cancer cell lines. Heparan sulfate disaccharides extracted from biological samples following actinase and heparinase incubation and derivatized using reductive amination with 2-aminoacridone. Derivatized disaccharides were analyzed used UPLC-MS with single ion monitoring. Eight HS disaccharide subunits were separated and quantified from HS and cell lines in eleven minutes per sample. In all samples the most abundant subunits present were the unsulfated ΔUA-GlcNAc, ΔUA-GlcNAc,6S and ΔUA,2S-GlcNS,6S. There was considerable variation in the proportions and concentrations of disaccharides between different cell lines. Further studies are needed to examine the significance of these differences.

Topics: Aminoacridines; Chromatography, High Pressure Liquid; Disaccharides; Heparin; Heparin Lyase; Heparitin Sulfate; Humans; Mass Spectrometry; Neoplasms; Tumor Cells, Cultured

Hyaluronan (HA), chondroitin sulfate (CS), and heparan sulfate (HS) are glycosaminoglycans (GAGs) with a great importance in biological processes as they participate in functional cell properties, such as migration, adhesion, and proliferation. A perturbation of the quantity and/or the sulfation of GAGs is often associated with pathological conditions. In this chapter, we present valuable and validated protocols for the analysis of HA-, CS-, and HS-derived disaccharides after derivatization with 2-aminoacridone and by using the fluorophore-assisted carbohydrate electrophoresis (FACE). FACE is a well-known technique and a reliable tool for a fast screening of GAGs, as it is possible to analyze 16 samples at the same time with one electrophoretic apparatus. The protocols for the gel preparation are based on the variations of the acrylamide/bisacrylamide and buffer concentrations. Different approaches for the extraction and purification of the disaccharides of various biologic samples and pharmaceutical preparations are also stressed.

Topics: Aminoacridines; Animals; Buffers; Chemistry, Pharmaceutical; Chondroitin Sulfates; Chromatography, High Pressure Liquid; Disaccharides; Electrophoresis; Electrophoresis, Polyacrylamide Gel; Fluorescent Dyes; Glycosaminoglycans; Heparin; Heparitin Sulfate; Humans; Hyaluronic Acid; Lens Capsule, Crystalline; Mice; Pharmaceutical Preparations; Rats

A high-resolution online reverse-phase-high-performance liquid chromatography (RP-HPLC)-fluorescence detector (Fd)-electrospray ionization-mass spectrometry (ESI-MS) separation and structural characterization of disaccharides prepared from heparin (Hep), heparan sulfate (HS), and various low-molecular-weight (LMW)-Hep using heparin lyases and derivatization with 2-aminoacridone (AMAC) are described. A total of 12 commercially available Hep/HS-derived unsaturated disaccharides were separated and unambiguously identified on the basis of their retention times and mass spectra. The constituent disaccharides of various samples, including unfractionated Hep/HS, fast-moving and slow-moving Hep components, and several marketed products, were characterized. Furthermore, for the first time, the saturated trisulfated disaccharide belonging to the nonreducing end of Heps was detected as being approximately 2% in unfractionated samples and ~15-21% in LMW-Heps prepared by nitrous acid depolymerization. No desalting of the commercial products prior to enzymatic digestion or prepurification steps to eliminate any excess of AMAC reagent or interference from proteins, peptides, and other sample impurities before RP-HPLC-Fd-ESI-MS injection were necessary. This method has applicability for the rapid differentiation of pharmaceutical Heps and LMW-Heps prepared by means of different depolymerization processes and for compositional analysis of small amounts of samples derived from biological sources by using the highly sensitive fluorescence detector.

Topics: Aminoacridines; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Disaccharides; Fluorescent Dyes; Heparin; Heparin, Low-Molecular-Weight; Heparitin Sulfate; Spectrometry, Mass, Electrospray Ionization

Heparitinase I, a key lyase enzyme essential for structural analysis of heparan sulfate (HS), degrades HS domains that are undersulfated at glucuronyl residues through an elimination mechanism. Earlier studies employed viscosimetric measurements and electrophoresis to deduce the mechanism of action of heparitinase I and two other related lyases, heparitinase II and heparitinase III. However, these findings lack molecular evidence for the intermediates formed and could not distinguish whether the cleavage occurred from the reducing end or the nonreducing end. In the current study, 2-aminoacridone (2-AMAC)-labeled HS precursor oligosaccharides of various sizes were prepared to investigate the mechanism of heparitinase I-mediated depolymerization using sensitive and quantitative methodologies. Furthermore, fluorescent (2-AMAC) tagging of HS precursor oligosaccharides allowed us to distinguish fragments that result from cleavage of the substrates at various time intervals and sites farther away from the reducing and nonreducing ends of oligosaccharide substrates. This study provides the first direct molecular evidence for a predominantly random endolytic mechanism of cleavage of HS precursor oligosaccharides by heparitinase I. This robust strategy can be adapted to deduce the mechanism of action of other heparitinases and also to deduce structural information of complex HS oligosaccharides of biological importance.

Topics: Aminoacridines; Biocatalysis; Chromatography, High Pressure Liquid; Chromatography, Liquid; Enzyme Assays; Fluorescent Dyes; Heparin Lyase; Heparitin Sulfate; Molecular Weight; Oligosaccharides; Spectrometry, Mass, Electrospray Ionization; Staining and Labeling; Time Factors

Heparin (HE) and heparan sulfated glycosaminoglycans are well-known mediators of tissue development, maintenance and functions; the activities of these polysaccharides are depending mainly on their sulfate substitutions. The HE structure is also a very important feature in antithrombotic drug development, since the antithrombin binding site is composed by sequences of a specific sulfation pattern. The analysis of disaccharide composition is then a fundamental point of all the studies regarding HE/heparan sulfate glycosaminoglycan (and thereby proteoglycan) functions. The present work describes two analytical methods to quantify the disaccharides constituting HE and heparan sulfate chains. The use of PAGE of fluorophore-labeled saccharides and HPLC coupled with a fluorescence detector allowed in one run the identification of 90-95% of HE disaccharides and 74-100% of rat kidney purified heparan sulfate. Moreover, the protocol here reported avoid the N-sulfation disaccharides degradation, which may affect N-sulfated/N-acetylated disaccharides ratio evaluation. These methods could be also very important in clinical treatments since they are useful for monitoring the availability kinetics of antithrombotic drugs, such as low-molecular-weight HEs.

Topics: Acetylation; Aminoacridines; Animals; Chromatography, High Pressure Liquid; Electrophoresis, Polyacrylamide Gel; Fluorescent Dyes; Glycosaminoglycans; Heparin; Heparitin Sulfate; Rats; Sensitivity and Specificity; Swine

This work describes improved workup and instrumental conditions to enable robust, sensitive glycosaminoglycan (GAG) disaccharide analysis from complex biological samples. In the process of applying CE with LIF to GAG disaccharide analysis in biological samples, we have made improvements to existing methods. These include (i) optimization of reductive amination conditions, (ii) improvement in sensitivity through the use of a cellulose cleanup procedure for the derivatization, and (iii) optimization of separation conditions for robustness and reproducibility. The improved method enables analysis of disaccharide quantities as low as 1 pmol prior to derivatization. Biological GAG samples were exhaustively digested using lyase enzymes, the disaccharide products and standards were derivatized with the fluorophore 2-aminoacridone and subjected to reversed polarity CE-LIF detection. These conditions resolved all known chondroitin sulfate (CS) disaccharides or 11 of 12 standard heparin/heparan sulfate disaccharides, using 50 mM phosphate buffer, pH 3.5, and reversed polarity at 30 kV with 0.3 psi pressure. Relative standard deviation in migration times of CS ranged from 0.1 to 2.0% over 60 days, and the relative standard deviations of peak areas were less than 3.2%, suggesting that the method is reproducible and precise. The CS disaccharide compositions are similar to those obtained by our group using tandem MS. The reversed polarity CE-LIF disaccharide analysis protocol yields baseline resolution and quantification of heparin/heparan sulfate and CS/dermatan sulfate disaccharides from both standard preparations and biologically relevant proteoglycan samples. The improved CE-LIF method enables disaccharide quantification of biologically relevant proteoglycans from small samples of intact tissue.

Topics: Aminoacridines; Animals; Cartilage; Cattle; Cellulose; Chondroitin Sulfates; Dermatan Sulfate; Disaccharides; Electrophoresis, Capillary; Fluorescence; Glycosaminoglycans; Heparin; Heparitin Sulfate; Humans; Lyases; Reproducibility of Results; Sensitivity and Specificity

In quest for high sensitivities, we developed an ultrahigh capillary electrophoresis (CE) method for the structural analysis of heparin and heparan sulfate (HS) in biologic samples. Heparin and HS were digested with an equi-unit mixture of heparin lyases I, II and III and the obtained Delta-disaccharides were derivatized with the fluorophore 2-aminoacridone. All known twelve non-, mono-, di- and trisulfated Delta-disaccharides were completely resolved in a single run, using 50 mM phosphate buffer, pH 3.5, and reversed polarity at 30 kV. Relative standard deviation in migration times and peak areas as well as day-to-day variance ranged from 0.9 to 2.4%, suggesting a reproducible and precise method. Detection of 2-aminoacridone (AMAC)-derivatives of Delta-disaccharides by UV at 255 nm showed 2.8 and 10 times higher sensitivity than that of derivatized and non-derivatized ones at 232 nm. Laser-induced fluorescence detection with an Ar-ion laser source showed an approximately 100 times higher sensitivity than that obtained at 232 nm of the non-derivatized species. Application of this method to quantitative analysis of Delta-disaccharides derived from porcine intestinal mucosa heparin and bovine kidney HS showed excellent agreement with previously published methods, suggesting an accurate method. The developed method can be easily applied for the disaccharide analysis of heparin/HS at the attomole level with high accuracy, for distinguishing between heparin and HS and may be of value for studying their interactions with matrix effective molecules.

Topics: Aminoacridines; Carbohydrate Sequence; Disaccharides; Electrophoresis, Capillary; Heparin; Heparitin Sulfate; Lasers; Molecular Sequence Data; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet

A series of disaccharides derived from chondroitin sulfate and heparin/heparan sulfate were derivatized at their reducing ends with the fluorophore 2-aminoacridone. The resulting labeled compounds derived from chondroitin sulfate or heparin/heparan sulfate were well separated and could be quantified by capillary electrophoresis and HPLC with a fluorescence detector. This method was successfully applied to the analysis of the disaccharide composition of sulfated tetra- and hexasaccharides derived from chondroitin sulfate and heparin/heparan sulfate. Remarkably, the saturated and the corresponding unsaturated chondrodisaccharides, the structures of which differ only in their nonreducing terminal uronic acid residues, were also well separated from each other by capillary electrophoresis. This facilitated disaccharide composition analysis of saturated chondrooligosaccharides prepared by testicular hyaluronidase digestion as well as unsaturated chondro- and heparin/heparan sulfate-oligosaccharides prepared by digestion with chondroitinases and heparitinases. The developed method employing the derivatization by 2-aminoacridone in conjunction with capillary electrophoresis or HPLC with a fluorescence detector allows a simple, sensitive, and quantitative disaccharide composition analysis of the glycosaminoglycan-derived oligosaccharides.

Topics: Aminoacridines; Chondroitin Lyases; Chondroitin Sulfates; Chromatography, High Pressure Liquid; Cystine; Disaccharides; Electrophoresis, Capillary; Fluorescent Dyes; Fluorometry; Glycosaminoglycans; Heparin; Heparitin Sulfate; Oligosaccharides; Polysaccharide-Lyases