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The highly glycosylated bone sialoprotein (BSP) is an abundant non-collagenous phosphoprotein in bone which enhances osteoblast differentiation and new bone deposition in vitro and in vivo. However, the structural details of its different glycosylation linkages have not been well studied and their functions in bone homeostasis are not clear. Previous studies suggested that the O -glycans, but not the N -glycans on BSP, are highly sialylated. Herein, we employed tandem mass spectrometry (MS/MS) to demonstrate that the N -glycanson the recombinant human integrin binding sialoprotein (rhiBSP) are also enriched in sialic acids (SAs) at their termini. We also identified multiple novel sites of N -glycan modification. Treatment of rhiBSP enhances osteoblast differentiation and mineralization of MC3T3-E1 cells and this effect could be partially reversed by efficient enzymatic removal of its N -glycans. Removal of all terminal SAs has a greater effect in reversing the effect of rhiBSP on osteogenesis, especially on mineralization, suggesting that sialylation at the termini of both N -glycans and O -glycans plays an important role in this regulation. Moreover, BSP-conjugated SAs may affect mineralization via ERK activation of VDR expression. Collectively, our results identified novel N -glycans enriched in SAs on the rhiBSP and demonstrated that SAs at both N - and O -glycans are important for BSP regulation of osteoblast differentiation and mineralization in vitro. [ABSTRACT FROM AUTHOR]

Abstract: Liquid chromatography–mass spectrometry was applied to determine the action pattern of different chondroitin lyases. Two commercial enzymes, chondroitinase ABC (Proteus vulgaris) and chondroitinase ACII (Arthrobacter aurescens), having action patterns previously determined by viscosimetry and gel electrophoresis were first examined. Next, the action patterns of recombinant lyases, chondroitinase ABC from Bacteroides thetaiotaomicron (expressed in Escherichia coli) and chondroitinase AC from Flavobacterium heparinum (expressed in its original host), were examined. Chondroitin sulfate A (CS-A, also known as chondroitin-4-sulfate) was used as the substrate for these four lyases. Aliquots taken at various time points were analyzed. The products of chondroitinase ABC (P. vulgaris) and chondroitinase AC (F. heparinum) contained unsaturated oligosaccharides of sizes ranging from disaccharide to decasaccharide, demonstrating that both are endolytic enzymes. The products afforded by chondroitinase ABC (B. thetaiotaomicron) and chondroitinase ACII (A. aurescens) contained primarily unsaturated disaccharide. These two exolytic enzymes showed different minor products, suggesting some subtle specificity differences between the actions of these two exolytic lyases on chondroitin sulfate A. [Copyright &y& Elsevier]

Isobaric oligosaccharides enzymatically prepared from hyaluronic acid (HA) and N-acetylheparosan (NAH), were distinguished using tandem mass spectrometry. The only difference between the two series of oligosaccharides was the linkage pattern (in HA 1→3 and in NAH 1→4) between glucuronic acid and N-acetylglucosamine residues. Tandem mass spectrometry afforded spectra in which glycosidic cleavage fragment ions were observed for both HA and NAH oligosaccharides. Cross-ring cleavage ions 0,2An and 0,2An-h (n is even number) were observed only in GlcNAc residues of NAH oligosaccharides. One exception was an 0,2A2 ion fragment observed for the disaccharide from HA. These cross-ring cleavage fragment ions are useful to definitively distinguish HA and NAH oligosaccharides. [Copyright &y& Elsevier]

Abstract: A sensitive and selective liquid chromatographic–tandem mass spectrometric (LC–MS/MS) method was developed for the determination of serial chiral novel anticholinergic compounds of phencynonate in rat plasma. After a simple protein-precipitation using methanol, the post-treatment samples were separated on a CAPCELL UG120 column with a mobile phase of a mixture of methanol and water (35:65) containing 0.1% formic acid. The serial chiral analytes and internal standard (IS) were all detected by the use of selected reaction monitoring mode (SRM). The method of all serial chiral analytes developed was validated in rat plasma with a daily working range of 0.5–100ng/ml with correlation coefficient, R 2 ≥0.99 and a sensitivity of 0.5ng/ml as lower limit of quantification, respectively. This method was fully validated for the accuracy, precision and stability studies for all serial chiral analytes. The method proved to be accurate and specific, and was applied to the pharmacokinetic study of serial chiral novel anticholinergic compounds of phencynonate in rat plasma. [Copyright &y& Elsevier]

Negative-ion electrospray tandem mass spectrometry (ES-MS/MS) with collision-induced dissociation (CID) is attempted for sequence determination of alginate oligosaccharides, derived from polyanionic alginic acid, polymannuronate, and polyguluronate by partial depolymerization using either alginate lyase or mild acid hydrolysis. Sixteen homo- and hetero-oligomeric fragments were obtained after fractionation by gel-filtration and strong anion exchange high performance liquid chromatography. The product-ion spectra of these alginate oligosaccharides were dominated by intense B-, C-, Y-, and Z-type ions together with 0,2A- and 2,5A-ions of lower intensities. Internal mannuronate residues (M) produce weak but specific decarboxylated Zint-ions (Zint − 44 Da; int: denotes internal), which can be used for distinction of M and a guluronate residue (G) at an internal position. A reducing terminal M or G, although neither gives rise to a specific ion, can be identified by differences in the intensity ratio of fragment ions of the reducing terminal residue [2,5Ared]/[0,4Ared] (red: denotes reducing terminal). [Copyright &y& Elsevier]

A novel homogenous polysaccharide LPWF together with its three acid hydrolysis products LPWF1–3 were isolated and prepared from lotus plumule (germs of Nelumbo nucifera). LPWF was composed of rhamnose (Rha), arabinose (Ara), galactose (Gal), xylose (Xyl), and galacturonic acid (GalA) in the molar ratio of 7.3: 34.0: 7.0: 19.1: 32.6 with a molecular weight of 567.6 kDa. The structure of LPWF was elucidated by methylation and NMR analysis of LPWF1–3 and a follow-up structural assembling aided by high-resolution mass spectrometry mapping of oligosaccharides and ROSEY spectra. LPWF was characterized as an unusual pectin linked by rhamnogalacturonan I (RGI, composed of LPWF1–2) and xylogalacturonan (XGA, LPWF3). LPWF1 was an arabinan peeled from the RGI part with a 1,5-linked backbone branching on the O -2 position, while LPWF2 was the remaining part of RGI composed of Rha (36.1%), Gal (17.8%), and GalA (43.7%). LPWF3 was identified as the XGA part with a backbone of α-1,4-linked GalA and branches of mono-xylose substitutions on the O -3 of GalA. LPWF (25 μg/mL) demonstrated significant inhibitions on the expression of IL-1β, IL-6, and TNF-α in LPS-stimulated primary murine microglia cultures. LPWF1 and 2 showed selectively and significantly inhibitory activity against the expression of IL-1β. • Structure features of the pectin LPWF was determined by NMR and methylation. • Structural characterization of LPWF was elucidated by assembling three stepwise hydrolyzed fragments. • LPWF is speculated to be a linearly linked RGI and XGA pectin. • The pectin LPWF could significantly inhibit the expression of IL-1β, IL-6, and TNF-α. [ABSTRACT FROM AUTHOR]

Highlights • 1H-NMR of heparins from different animals show distinct clusters in PCA and k means analysis. • Disaccharides components of heparins from different animals show distinct clusters in PCA and k means. • Tetrasaccharides components of heparins from different animals show distinct clusters in PCA and k means. • Chemometric analysis could help predict the heparin animal source and detect blending. Abstract Heparin is a polysaccharide anticoagulant drug isolated from animal tissues. There have been concerns on the safety and security of the heparin supply chain since 2007-8 when a contamination crisis led to its disruption. The current study applies a suite of modern analytical techniques to porcine, bovine and ovine intestinal mucosal heparins. These techniques include structural analysis by nuclear magnetic resonance spectrometry, disaccharide compositional analysis, bottom-up analysis of tetrasaccharides corresponding to heparin's antithrombin III binding site. Chemometric analysis was then applied to understand how these structural differences to predict the animal/tissue source of heparin and to help detect blending of heparins from various sources. [ABSTRACT FROM AUTHOR]

Sulfur mustard (SM) is a powerful vesicant and one of the most harmful chemical warfare agents. Although having been studied for a long time, it is still difficult to fully elucidate the mechanisms of SM poisoning, and there is no effective antidote or specific treatment for SM injury. The investigations on toxicokinetics and tissue distribution of SM will help to understand its toxicity and provide a theoretical basis for pretreatment and therapy of SM poisoning. But the metabolic trajectory or fate of intact SM in vivo remains unclear, and there are insufficient experimental data to elucidate, due to its high reactivity and difficulty in biomedical sample analysis. In this paper, a sensitive method for the detection and quantification of intact SM in blood or tissues using isotope-dilution LC-MS/MS coupled with chemical conversion was developed. By transforming highly reactive SM into stable derivative product, the real concentration of intact SM in biological samples was obtained accurately. The toxicokinetics and tissue distribution studies of intact SM in rats were successfully profiled by the novel method after intravenous (10 mg/kg) or cutaneous administration (1, 3 and 10 mg/kg). The SM level in blood with peak time at 30-60 min determined in cutaneous exposure experiment was found much higher than previously reported, and the mean residence time in blood extended to 1-1.5 h. A significant accumulation of intact SM was observed in adipose tissues, including the perirenal fat, epididymal fat, subcutaneous fat and brown fat, in which the concentrations of SM were at least 15 times greater than those in non-adipose tissues in cutaneous exposed rats. The recovery of SM in body fat was calculated as 3.3 % of bioavailable SM (the bioavailability after cutaneous exposure was evaluated as 16 %). Thus, the adipose tissue was important for SM distribution and toxicity, which may pioneer a new model for both the prevention and treatment of SM exposure. [ABSTRACT FROM AUTHOR]

• Strategy of LC-QTOF/MS with a hypothetical database for carrageenan profiling. • In-source fragmentation of sulfated oligosaccharides was identified. • Peeling reaction occurs at alkaline conditions thus generating odd oligosaccharides. Carrageenan (CGN) belongs to the sulfated polysaccharides family that is commonly used in the food industry. For oligosaccharide analysis, a liquid chromatography quadrupole time-of-flight/mass spectrometry strategy was developed using a hypothetical database. There are 2100 structures in the developed hypothetical κ-CGN database. To eliminate false-positive results, three approaches were used, including size exclusion chromatography with mass spectrometry, which differentiates the loss of sulfated groups caused by the hydrolysis process or the ionization process. Profiling of acidic hydrolysis products of κ-CGN was found that after 12 h of HCl cultivation, the κ-CGN was hydrolyzed to oligosaccharides lower than the degree of polymerization 10, breaking the α-1,3-glycoside linkage and producing even-numbered oligosaccharides. Another finding was that the pH at which acidic hydrolysis is terminated affects the generation of even and odd oligosaccharides. Peeling reaction occurs at the reduction end 4-linked-3,6-anhydrous- d -galactose when adjusted to alkaline conditions, thus generating odd oligosaccharides. [ABSTRACT FROM AUTHOR]

Investigation of the action pattern of enzymes acting on carbohydrates is challenging, as both the substrate and the digestion products are complex mixtures. Dextran and its enzyme-derived oligosaccharides are widely used for many industrial applications. In this work, a new method relying on ultra-performance hydrophilic interaction liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UP-HILIC- Q/TOF-MS/MS) was developed to analyze a complex mixture of dextran oligosaccharide products to determine the action pattern of dextranase. No derivatization of oligosaccharides was required and the impact of the α- and β-configurations of the native oligosaccharides on the chromatographic separation was eliminated. The 1→6, 1→3, 1→4 backbone linkages and the branch linkages of these oligosaccharides were all distinguished from diagnostic ions in their MS/MS spectra, including fragments corresponding to A, A, A, B-HO, A, and A. The sequences of the oligosaccharide products were similarly established. Thus, the complex oligosaccharide mixtures in dextran digestion products were profiled and identified using this method. The more enzyme-resistant structures in dextran were established using much less sample, labor, time, and uncertainty than in previous studies. This method provides an efficient, sensitive, and straightforward way to monitor the entire process of digestion, establish the action pattern of the dextranase from Penicillium sp., and to support the proper industrial application of dextranase. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Porcine intestinal mucosa heparin was partially depolymerized by recombinant heparinase 1 (heparin lyase 1, originating from Flavobacterium heparinum and expressed in Escherichia coli) and then fractionated, leading to the isolation of 22 homogeneous oligosaccharides with sizes ranging from disaccharide to hexadecasaccharide. The purity of these oligosaccharides was determined by gel electrophoresis, strong anion exchange and reversed-phase ion-pairing high-performance liquid chromatography. The molecular mass of oligosaccharides was determined using electrospray ionization-mass spectrometry and their structures were elucidated using one- and two-dimensional nuclear magnetic resonance spectroscopy at 600 MHz. Five of the characterized oligosaccharides represent new compounds. The most prominent oligosaccharide comprises the common repeating unit of heparin, ΔUA2S-[-GlcNS6S-IdoA2S-]n-GlcNS6S, where ΔUA is 4-deoxy-α-l-threo-hex-4-eno-pyranosyluronic acid, GlcN is 2-deoxy-2-amino-d-glucopyranose, IdoA is l-idopyranosyluronic acid, S is sulfate and n = 0–7. A second prominent heparin oligosaccharide motif corresponds to ΔUA2S-[GlcNS6S-IdoA2S]n-GlcNS6S-IdoA-GlcNAc6S-GlcA-GlcNS3S6S (where n = 0–5 and GlcA is d-glucopyranosyluronic acid), a fragment of the antithrombin III binding site in heparin. The prominence of this second set of oligosaccharides and the absence of intact antithrombin III binding sites suggest that the -GlcNS3S6S-IdoA2S- linkage is particularly susceptible to heparinase 1. [ABSTRACT FROM AUTHOR]

Abstract: A simple, sensitive and reliable method was developed to determine simultaneously the concentrations of thienorphine and its metabolite thienorphine glucuronide conjugate in rat plasma by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The metabolite was identified by MS: thienorphine glucuronide conjugate. Sample preparation involved protein precipitation with methanol. Analytes were separated on Finnigan BetaBasic-18 column (150mm×2.1mm i.d., 5μm) using methanol: water: formic acid (56:44:0.1, v/v/v) as mobile phase at a flow rate of 0.2ml/min. The method had a linear calibration curve over the concentration range of 0.1–50ng/ml for thienorphine and 2–1000ng/ml for thienorphine glucuronide conjugate, respectively. LOQ of thienorphine and thienorphine glucuronide conjugate was 0.1 and 2ng/ml, respectively. The intra- and inter-batch precisions were less than 12% and their recoveries were greater than 80%. Pharmacokinetic data of thienorphine and its metabolite thienorphine glucuronide conjugate obtained with this method following a single oral dose of 3mg/kg thienorphine to rats were also reported for the first time. [Copyright &y& Elsevier]

Abstract: A sensitive and specific high-performance liquid chromatography–tandem mass spectrometry method (LC/ESI/MS) was developed and validated for the identification and quantification of the novel lead compound of anticholinergic drug thiencynonate in rat plasma. The analytes were determined using positive electrospray ionization mass spectrometry in the selected reaction ion monitoring (SRM). The chromatography separation was on BetaBasic-18 column (150mm×2.1mm i.d., 3μm). The mobile phase was composed of methanol–water (70:30, v/v), containing 0.5‰ formic acid, which was pumped at a flow rate of 0.2ml/min. Phencynonate was selected as the internal standard (IS). Simultaneous MS detection of thiencynonate and IS was performed at m/z 364.4 (thiencynonate), m/z 358 (phencynonate), and the SRM of the two compounds were both at 156. Thiencynonate eluted at approximately 2.8min, phencynonate eluted at approximately 2.9min and no endogenous materials interfered with their measurement. Linearity was obtained over the concentration range of 1–100ng/ml in rat plasma. The lower limit of quantification (LLOQ) was reproducible at 1ng/ml in rat plasma. The precision measured was obtained from 2.47 to 9.28% in rat plasma. Extraction recoveries were in the range of 67.63–76.76% in plasma. This method was successfully applied to the identification and quantification of thiencynonate in pharmacokinetic studies. [Copyright &y& Elsevier]

Abstract: A sensitive and specific high-performance liquid chromatographic assay with electrospray ionization mass spectrometry detection (LC-ESI-MS) has been developed and validated for the identification and quantification of the novel anticholinergic drug phencynonate in rat blood and urine. The sample pretreatment involves basification and iterative liquid–liquid extraction with ethyl ether–dichloromethane (2:1, v/v) solution, followed by LC separation and positive electrospray ionization mass spectrometry detection. The chromatography was on BetaBasic-18 column (150mm×2.1mm i.d., 3μm). The mobile phase was composed of methanol–water (85:15, v/v), containing 0.5‰ formic acid, which was pumped at a flow-rate of 0.2ml/min. Thiencynonate was selected as the internal standard (IS). Simultaneous MS detection of phencynonate and IS was performed at m/z 358.4 (phencynonate), m/z 364 (thiencynonate), and the selected reaction ion monitoring (SRM) of the two compounds was at 156. Phencynonate eluted at approximately 5.25min, thiencynonate eluted at approximately 5.10min and no endogenous materials interfered with their measurement. Linearity was obtained over the concentration range of 1–100ng/ml in rat blood and 1–500ng/ml in rat urine. The lower limit of quantification (LLOQ) was reproducible at 1ng/ml in both of rat blood and urine. The precision measured was obtained from 2.92 to 9.76% in rat blood and 4.17 to 9.76% in rat urine. Extraction recoveries were in the range of 69.57–79.49% in blood and 56.85–64.86% in urine. This method was successfully applied to the identification and quantification of phencynonate in pharmacokinetic studies. [Copyright &y& Elsevier]

• A method with MHC 2D-LC linked to MS was developed to analyze digested heparin. • SAX is the first dimensional, SEC is the second dimensional chromatography. • 8 common dp2, 8 enzyme resistant dp4 & a heparin–core protein link dp4 were observed. • Composition result implied their structure, activity and production properties. Heparin is a linear sulfated polysaccharide. It is composed of a repeating disaccharide unit with different sulfo patterns. The compositional analysis after heparin was decomposed to disaccharides and enzyme resistant domains is an important way to delve into its structure. Strong anion exchange (SAX) chromatography is commonly used for the compositional analysis due to its high resolution, stability and capability of quantitation. However, nonvolatile salt in mobile phase is not compatible with MS, then the structural domains cannot be identified without standards. Here, a new two-dimensional liquid chromatography system, multiple heart cut (MHC), was developed and linked to mass spectrometry (MS) directly to provide a comprehensive analysis of enzyme digested heparin. SAX was applied as the first dimensional chromatography, in which 17 peaks were observed and integrated in the digested heparin. Size-exclusion chromatography (SEC) was used as the second dimensional chromatography to desalt efficiently. Structural information of each component was then obtained with MS, including eight common disaccharides, eight enzyme resistant tetrasaccharides and a heparin–core protein linkage domain. The comparison of enzyme digested heparins obtained from different vendors using this system suggested their similar major structure and activity, but slightly different production processes. [ABSTRACT FROM AUTHOR]