High-performance liquid chromatography of reducing carbohydrates as strongly ultraviolet-absorbing and electrochemically sensitive 1-phenyl-3-methyl-5-pyrazolone derivatives

Quantitative uronic acid analysis of the otoconial membrane of the guinea pig

Histochemical and biochemical studies have shown that the otoconial membrane, as well as the tectorial membrane and the cupula, contains glycoproteins and proteoglycans. However, uronic acids, which are essential elements of glycosaminoglycans (GAGs), have not so far been directly detected or quantitatively measured in inner ear samples. In the present study, we quantitatively analyzed the glucuronic acid (GlcA) content of the otoconial membrane of the guinea pig by methanolysis combined with reversed-phase high-performance liquid chromatography (RP-HPLC). The utricular otoconial membrane was treated with thermolysin to separate the supernatant (OM-sup; gelatinous layer) and precipitate (OM-ppt; otoconia). The samples were then subjected to methanolysis followed by brief TFA hydrolysis, incubated with 1-phenyl-3-methyl-5-pyrazolone for labeling, and then analyzed by RP-HPLC coupled with the detection of UV absorbance at 245 nm. The GlcA contents of OM-sup and OM-ppt were 2.1 and 5.8 pmol/100 ng protein, respectively. Based on this result, GlcA-containing GAGs estimated as (GlcA+monosulfo-N-acetylhexosamine)n would be 1.0% of protein in OM-sup and 2.61% of protein in OM-ppt, indicating that this type of glycoconjugate is a minor component in both fractions. It is, accordingly, presumed that both the gelatinous layer and otoconia of the otoconial membrane have totally different properties from those of the tectorial membrane and cartilaginous matrix, which contain abundant GAGs.

An angiogenic protein from bovine serum and milk--purification and primary structure of angiogenin-2

Bovine serum and milk contain a basic angiogenic protein that binds tightly to placental ribonuclease inhibitor. It was purified from both sources by ion-exchange and reversed-phase chromatographies. Its amino acid sequence revealed that it is a member of the ribonuclease superfamily. It contains 123 amino acids in a single polypeptide chain, is cross-linked by three disulfide bonds, is glycosylated at Asn33, and is 57% identical to bovine angiogenin. The amino-terminal and carboxyl-terminal residues are pyroglutamic acid and proline, respectively. The protein has ribonucleolytic activity that is similar to, but somewhat lower than, that of bovine angiogenin, i.e. very low relative to RNase. It is angiogenically potent on chicken chorioallantoic membrane, but less so than angiogenin. The sequence and activities demonstrate that this protein is a second, distinct, member of the angiogenin sub-family of pancreatic ribonucleases, and is referred to as angiogenin-2.

Oligosaccharide characterization and quantitation using 1-phenyl-3-methyl-5-pyrazolone derivatization and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatives of monosaccharides, maltooligosaccharides, and oligosaccharides enzymatically released from asparagine-linked sites in ribonuclease B and fetuin have been investigated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Use of the matrix 2,6-dihydroxyacetophenone containing diammonium hydrogen citrate (DHAP/DAHC) resulted in predominance of protonated over sodiated pseudomolecular ions of PMP-derivatized oligosaccharides. By comparison, the matrices alpha-cyano-4-hydroxycinnamic acid and 2,5-dihydroxybenzoic acid resulted in predominantly sodiated pseudomolecular ions. In addition, tendencies for fragmentation of PMP-oligosaccharide derivatives were significantly lower with DHAP/DAHC which enabled meaningful data to be obtained in reflector mode, even for samples with high excipient levels. The relative magnitude of the ion signals for PMP-derivatized maltooligosaccharides and ribonuclease B oligosaccharides correlated well with the oligomer distribution apparent by HPLC. PMP-maltohexose was used as an internal standard to quantitate PMP-oligosaccharides from ribonuclease B and asialofetuin in crude derivatization mixtures. A linear relationship was observed between the ratio of the intensities of pseudomolecualr ions and the amount of glycoprotein derivatized. The limit of detection for the major oligosaccharide of each protein was reached with ca. 3 micrograms of glycoprotein but may be further enhanced by optimization of sample handling. PMP derivatives of sialylated fetuin oligosaccharides were readily detected as protonated pseudomolecular ions by linear mode analyses. By comparison, reflector mode analyses revealed substantially reduced magnitudes of protonated pseudomolecular ions and considerable post-source fragmentation of sialic acid residues. The PMP derivatives of fetuin oligosaccharides were also amenable to exoglycosidase treatment as shown by the mass shifts found upon treatment with sialidase.

Structural characterization of N-linked oligosaccharides from cellobiohydrolase I secreted by the filamentous fungus Trichoderma reesei RUTC 30

We have characterized the primary structures of the predominant N-linked oligosaccharides on cellobiohydrolase I from the filamentous fungus Trichoderma reesei RUTC30. Different enzymatic and chromatographic techniques were used to analyze six oligosaccharides. The combined data showed that the fungal carbohydrates have a core structure that is identical to the mammalian N-linked core. In the bulk of the N-glycans, the alpha-1,3 arm is extended with two mannoses and a glucose, suggesting incomplete processing of the oligosaccharides in the endoplasmic reticulum. The alpha-1,6 arm shows a remarkable heterogeneity: in addition to alpha-1,2-Man and alpha-1,6-Man, the presence of a terminal mannose alpha-1,6-phosphodiester was observed. This latter substituent has not been characterized before on mannosidase-processed N-glycan and its function and synthesis pathway are entirely unknown. The predominant N-glycans on cellobiohydrolase I can be represented as follows: GlcMan8GlcNAc2, GlcMan7GlcNAc2, Man7GlcNAc2, ManPGlcMan7GlcNAc2, GlcMan5GlcNAc2 and Man5GlcNAc2.

Comparison of the sensitivities of various derivatives of oligosaccharides in LC/MS with fast atom bombardment and electrospray ionization interfaces

Sensitivities of the following derivatives of oligosaccharides in MS and LC/MS with frit FAB and ESI interfaces were compared under the conditions where samples were supplied to the probes in solutions at constant rates: 2-aminopyridine, 4-aminobenzoic acid ethyl ester (ABEE), 1-phenyl-3-methyl-5-pyrazolone (PMP) as well as 4-methoxyphenyl analogue, 2-aminoethanethiol, and 2-aminobenzenethiol. In FAB-MS, maltopentaose labeled with ABEE gave the most abundant [M + H]+ ions in positive ion mode when ionized in thioglycerol or glycerol matrix supplied in 50% (v/v) aqueous methanol. The lowest limit of detection was obtained for this compound in these matrices in water. The [M - H]- ion in negative ion mode was also abundant in all matrices examined in both 50% (v/v) aqueous methanol and water. On the other hand PMP derivatives gave the highest sensitivities in ESI-MS under the optimized conditions. On the basis of these findings, authentic oligosaccharides and oligosaccharides derived from a few glycoprotein samples were analyzed by LC/MS with frit FAB and ESI interfaces. The results indicated the usefulness of these derivatives for simultaneous microanalysis of oligosaccharides.

High-resolution glycoprotein analysis using capillary electrophoresis

The high-resolution separation achievable with capillary electrophoresis has been applied successfully to the analysis of glycoproteins. Inherent in the implementation of this technology for glycoprotein analysis is the use of specific buffer additives. Bifunctional cationic reagents, such as simple alkyl chains bearing terminal amino or quaternary ammonium groups, have been particularly useful for the analysis of ovalbumin, an excellent model glycoprotein. Although dynamic coating of the capillary wall and the subsequent decrease in protein-wall interactions in known to be key in the effectiveness of these additives, much remains to be learned regarding the mechanism through which they function.

High-performance liquid chromatographic mapping of the oligosaccharides released from the humanised immunoglobulin, CAMPATH 1H

A sensitive and reproducible method for the routine mapping of oligosaccharides in a humanised immunoglobulin (IgG) is described. The method involves the enzymic release of intact glycans using the endoglycosidase glycopeptidase-F, and subsequent derivatisation with 1-phenyl-3-methyl-5-pyrazolone to facilitate analysis by high-performance liquid chromatography (HPLC). The heterogeneous oligosaccharide chains are separated by a phosphate buffer-acetonitrile gradient reversed-phase HPLC method and monitored by ultraviolet detection at 245 nm, allowing the detection of picomole amounts. A number of standard oligosaccharides are similarly derivatised to enable classification of the types of structures present from a comparison of retention times.

Intestinal permeability, circulating endotoxin, and postoperative systemic responses in cardiac surgery patients

OBJECTIVES

To determine whether intestinal permeability increases during cardiac operations, and whether the degree of endotoxemia is related to this increase. Furthermore, to determine whether intestinal permeability is related to the hemodynamic state during operation and to postoperative systemic responses.

DESIGN

Prospective study.

SETTING

University hospital.

PARTICIPANTS

Twenty-three male patients undergoing elective coronary artery bypass surgery.

INTERVENTIONS

Before surgery and during the fifth postoperative day, 100 mL of a solution containing L-rhamnose and cellobiose were administered orally.

MEASUREMENTS AND MAIN RESULTS

Intestinal permeability was assessed by measuring the urinary excretion of L-rhamnose and cellobiose. Endotoxin concentrations in blood and prime fluid, hemodynamics, oxygen consumption, gas exchange, fluid balance, and the dose of vasoactive drugs were measured. Systemic responses were assessed by measuring hypermetabolism, circulatory support, and gas exchange. Intestinal permeation of cellobiose, reflecting paracellular transport, significantly increased during operation (p < 0.01), and correlated with the amount of circulating endotoxin (r2 = 0.46; p < 0.01). A high dose of ephedrine administered during operation, low baseline central venous pressure, and a less positive fluid balance during operation were associated with high intestinal permeability (r2 = 0.7; p < 0.01). Intestinal permeability was related to postoperative systemic responses (r2 = 0.49; p < 0.01).

CONCLUSIONS

This study shows that during elective coronary artery bypass operations intestinal permeability between cells may increase. The degree of endotoxemia is related to this increase. Increased intestinal permeability is related to the use of ephedrine, especially during hypovolemia, and to postoperative systemic responses. Although a causative relation is not shown, these results might indicate that hypovolemia and vasoconstriction should be avoided during the operation.

Multi-dimensional mapping of pyridylamine-labeled N-linked oligosaccharides by capillary electrophoresis

A simple, sensitive and reproducible multi-dimensional capillary electrophoresis (CE) oligosaccharide mapping method is reported. The structures of 20 identified N-linked oligosaccharides have been assigned mapping positions from which co-migrating unknown oligosaccharides can be characterized. The separation protocols developed have been demonstrated to separate both charged and neutral oligosaccharides. One dimension involves electroendosmotic flow-assisted CE in a sodium acetate buffer, pH 4.0. A second dimension involves separation based on borate complexation electrophoresis in a polyethylene glycol-containing buffer. A third dimension developed specifically for neutral oligosaccharides, using a sodium phosphate buffer, pH 2.5, has been shown to resolve neutral species not able to be separated by the other two dimensions. Thus, a three-dimensional map was generated to facilitate structural characterization of these oligosaccharides.

Separation of neutral carbohydrates by capillary electrophoresis

The basic strategies for analysis of neutral carbohydrates by capillary electrophoresis are summarized. Neutral carbohydrates are dissociated in strong alkali to give anions, hence they can be separated directly by zone electrophoresis based on the difference between their dissociation constants. However, neutral carbohydrates are not electrically charged under normal conditions. Therefore, they should be converted to ions prior to or during analysis. Precapillary introduction of a basic or an acidic group to a neutral carbohydrate gives the derivative positive (in acidic media) or negative (in alkaline media) charge, respectively. The derivatives thus obtained can be separated by zone electrophoresis. Analysis of carbohydrates in a carrier containing an oxyacid salt (such as sodium borate) or an alkaline metal salt (such as calcium acetate) causes in situ conversion to anionic or cationic complexes, respectively, which are separated by zone electrophoresis. The effective uses of electrokinetic chromatography in sodium dodecyl sulfate micelles for hydrophobic derivatives (such as 1-phenyl-3-methyl-5-pyrazolone derivatives) and size-exclusion electrophoresis in gel-packed capillaries for size-different oligosaccharides are also discussed. Each separation mode has its inherent method(s) for detection, which are also described here.

Development of electrophoretic conditions for the characterization of protein glycoforms by capillary electrophoresis-electrospray mass spectrometry

A capillary electrophoresis (CE) method using acidic buffers and capillaries coated with Polybrene, a cationic polymer has been developed for the separation of glycoproteins and glycopeptides. Electrophoretic conditions have been optimized to provide resolution of individual glycoforms observed for different glycoprotein preparations. These conditions were found to be entirely compatible with the operation of electrospray mass spectrometry (ESMS), which facilitated the assignments of possible carbohydrate compositions of glycopeptides arising from digests of glycoproteins. By using operating conditions enhanced the formation of oxonium fragment ions prior to mass spectral analysis, selective identification of glycopeptides was achieved for complex samples such as those from proteolytic digests or chemical cleavages. Examples of applications are presented for ribonuclease B, ovalbumin, horseradish peroxidase, and a lectin from Erithrina corallodendron using both CE-ESMS and CE with ultraviolet detection (CE-UV).

Preparative purification of tyrosinamide N-linked oligosaccharides

N-linked oligosaccharides from glycoproteins can be either analyzed on a sub-nanomole scale or preparatively purified on a multi-micromole scale. Each goal necessitates a unique analytical strategy often involving oligosaccharide derivatization to enhance separation and detection. Tyrosinamide-oligosaccharides were developed to facilitate the preparative purification of N-linked oligosaccharides. These have found many uses in oligosaccharide remodeling, in the preparation of neoglycoconjugates, in developing receptor probes, and even as analytical standards in chromatography. This review discusses progress in the preparation of tyrosinamide-oligosaccharides from different glycoproteins and their utility in glycobiology research.

Carbohydrate composition of stereociliary glycocalyx of the utricle of guinea pig inner ear

The carbohydrate composition of the stereociliary glycocalyx of the utricle was analysed quantitatively. The utricular sensory epithelium was collected from adult albino guinea pigs, and its apical surface structure was blotted onto a PVDF membrane, which was then subjected to acid hydrolysis. The hydrolysate was treated with 1-phenyl-3-methyl-5-pyrazolone for labelling and analysed by reversed-phase HPLC coupled with detection of UV absorbance at 245 nm. Man, GlcN, GaIN, Glc, Gal and Fuc were detected and estimated to be 211, 219, 46, 1,270, 266 and 36 pmoles per 10 utricular maculae, respectively. The presence of Man indicates the presence of N-linked glycoconjugates, and the considerable amounts of GLcN and Gal suggest the presence of complex-type N-glycosides, poly-lactosamine and/or keratan sulfate. The relatively low GaIN content indicates that O-glycosides, chondroitin sulfates and GaINAc-containing glycosphingolipids, i.e. gangliosides and globosides, are minor components. Electronmicroscopic and confocal laser scanning microscopic observations revealed that the blotted apical surface structure constituted mostly the ciliary bundle. Consequently, the observed carbohydrate composition is probably that of the stereociliary glycocalyx of the utricular sensory epithelium.

Disaccharide analysis of the skin glycosaminoglycans in chronically ultraviolet light-irradiated hairless mice

The alteration of main disaccharide units in the skin of hairless mice (HOS:Hr 1) after chronic and repeated ultraviolet light (UV) radiation was investigated using high performance liquid chromatography after labeling with 1-phenyl-3-methyl-5-pyrazolone. The total amount of main disaccharide units increased by UVA irradiation at the 24th and 36th weeks in comparison with the control. At the 36th week UVA significantly increased hyaluronic acid-derived delta Di-HA (HA). Dermatan sulfate-derived delta Di 4S (DS) and chondroitin sulfate-derived delta Di-4S (CS) increased at the 36th week, although not statistically significant. The total amount of main disaccharide units was increased significantly by UVB irradiation at the 24th week as compared with the control. Concerning the compositional change in main disaccharide units after a 36-week repeated exposure, the decrease in delta Di-HA(HA) and the increase in delta Di-4S (DS) were found in the order of control, UVA- and UVB-irradiated groups. These results, for the first time, indicate the precise alterations of glycosaminoglycans, both in the total amount and in the composition, confirming the previous histochemical findings. This disaccharide analysis should provide a useful method to examine the biochemical changes of skin glycosaminoglycans in photoaging.

Fluorophore-assisted carbohydrate electrophoresis technology and applications

Carbohydrates, in particular the complex carbohydrates conjugated to proteins and lipids, have important functions in a variety of biological systems. Their isolation and structural determination--prerequisites for elucidation of their biological functions--have been technical challenges for many decades. Almost all available chromatographic and electrophoretic methods as well as NMR and MS have been applied to carbohydrate analysis but none has proved satisfactory in terms of simplicity, sensitivity, reproducibility, cost and requirement for materials. Recently, a technique called fluorophore-assisted carbohydrate electrophoresis was developed which is very promising. It separates fluorescently-labeled carbohydrates on polyacrylamide gels and uses a charge-coupled device camera to detect and quantitate the products. This review describes the principles of the method and its applications to several aspects of research on carbohydrate-containing biological biomolecules.

Heterogeneity of the covalent structure of the blue copper protein umecyanin from horseradish roots

The covalent structure of umecyanin has been determined by a combination of classical Edman degradation sequence analysis and plasma desorption, laser desorption, and electrospray ionization mass spectrometry. The preparation appeared to contain two isoforms having either a valine (75%) or an isoleucine (25%) residue at position 48. The polypeptide chain of 115 amino acids is strongly heterogeneous at its C-terminal end as a result of proteolytic cleavages at several places within the last 10 residues. The major fraction of the umecyanin preparation is only 106 residues long. The C-terminal tail 107-115 contains mainly alanine and glycine residues and a single hydroxyproline residue. In the native protein there is a disulfide bridge between Cys 91 and Cys 57, but in the apoprotein there is a disulfide shift that involves Cys 91 and one of the four copper binding residues (Cys 85). The three other ligand binding residues are His 44, His 90, and Gln 95. This tetrad of amino acids is the same as occurs in other type 1 copper proteins from plants such as cucumber peeling cupredoxin and lacquer tree stellacyanin. The umecyanin isoforms are glycoproteins with a glycan core having the same carbohydrate composition as that of horseradish peroxidase, a fact that is convincingly supported thanks to the high accuracy of the electrospray mass spectrometric technique. We suggest that the glycan may play a role in the association of the protein to the cellular membrane, but the precise functional role of umecyanin remains to be determined. We also discuss the evolutionary position of umecyanin in relation to the type 1 copper proteins in general.

Purification of isotransferrins by concanavalin A sepharose chromatography and preparative isoelectric focusing

1. From pooled serum containing genetically homogeneous transferrin C1, transferrin was purified and separated in three fractions (tri-tri, bi-tri- and bi-bi-antennary transferrin C1), using Concanavalin A-Sepharose. 2. Each of these fractions was separated into its sialic acid-dependent subfractions by preparative isoelectric focusing. Sixteen iso-transferrin C1 fractions were obtained, which differed in their degree of glycan branching and/or their sialic acid content. 3. Preliminary carbohydrate analyses suggest that in some iso-transferrins the N-acetylglucosamine and the galactose content is lower than expected.

Carbohydrate depletion of immunoglobulin A1 by oral species of gram-positive rods

Bacterial deglycosylation of immunoglobulin Al (IgA1), the dominant isotype of antibody in the oral cavity, probably provides both nutrition as well as protection to the oral bacterial community. Representative strains of oral gram-positive rods were tested for their ability to remove carbohydrates from IgA1. Detection of sialic acids was performed by means of high-performance liquid chromatography (HPLC) separation (Aminex HPX-87H) and ultraviolet light absorption at 190 nm, and neutral carbohydrates were measured by HPLC separation (Capcell Pak C-18 SG 120) and ultraviolet light absorption at 245 nm after derivatization. Four strains of Actinomyces naeslundii, two strains of Corynebacterium matruchotii and one of two strains of Actinomyces odontolyticus partially or totally removed sialic acid, while two strains of Propionibacterium propionicus and the other strain of A. odontolyticus did not. Complete correlation was observed between sialic acid removal, neuraminidase activity measured with fluorogenic substrate and with one exception, altered immunoelectrophoretic mobility of IgA1. Only limited removal of other carbohydrates was observed with poor correlation to exoglycosidase activities measured with chromogenic substrates. Desialylation increases the susceptibility of glycoproteins, including IgA1, to proteolysis. Therefore, the desialylation of IgA1 by oral gram-positive rods may facilitate the proteolytic activities of other oral bacteria, and the concerted action may positively influence the survival of the bacteria in the oral community.

Disaccharide analysis of dermal fibroblast-derived glycosaminoglycans in the three-dimensional culture

We performed the quantitative and qualitative analysis on the main disaccharide units of glycosaminoglycans produced by human dermal fibroblasts in the 3-dimensional culture supplemented with L-ascorbic acid 2-phosphate (Asc 2-p) comparing with the monolayer culture system. The addition of Asc 2-p rendered fibroblasts to the organization of the dermis-like 3-dimensional structure in vitro without any pre-treatments with the plastic dish. Main disaccharide units were analyzed using HPLC after 1-phenyl-3-methyl-5-pyrasolone (PMP) labeling. The addition of Asc 2-p significantly increased the total amount of main disaccharide units and, furthermore, the composition revealed it to be more similar to that of the dermis. This 3-dimensional culture may offer a simple and useful system to investigate the glycosaminoglycan metabolism of human dermal fibroblasts in vitro.

Disaccharide analysis of the skin glycosaminoglycans in patients with Werner's syndrome

The disaccharide content of the chondroitinase-digestible glycosaminoglycans (GAGs) extracted from 6-mm skin punch biopsies from the atrophic and sclerotic skin of two patients with Werner's syndrome (WS) were determined using high-performance liquid chromatography after 1-phenyl-3-methyl-5-pyrazolone labelling. The total amount of main disaccharides was significantly decreased in the atrophic lesions of WS. In the atrophic forearm skin, the decrease in the main disaccharide unit of hyaluronic acid, delta Di-HA, and the increase in the ratio of the main disaccharide unit of dermatan sulphate, delta Di-4S, to delta Di-HA were significant vs. normal control (P < 0.01 and 0.05, respectively). The sclerotic skin showed an increase in delta Di-4S (DS) (P < 0.05) and a decrease in delta Di-HA (P < 0.02) compared with normal controls, as well as a significantly higher ratio of delta Di-4S (DS)/delta Di-HA compared with normal controls (P < 0.0002) and systemic sclerosis patients (SSc; P < 0.02). No other statistical difference was found in the amount of each main disaccharide unit between the sclerotic skin of WS and SSc. Histological examination revealed that the atrophic skin showed thinning of the dermis with a slight increase of fine collagen bundles, whereas the sclerotic skin demonstrated a thickened dermis with prominent deposition of fine collagen bundles in the deep dermis. In SSc, thickening of the whole dermis, composed of hyalinized or swollen collagen bundles, was found.(ABSTRACT TRUNCATED AT 250 WORDS)

A detailed structural characterization of ribonuclease B oligosaccharides by 1H NMR spectroscopy and mass spectrometry

The structures of ribonuclease B oligosaccharides have previously been shown to be high mannose type by methylation analyses and sequential exoglycosidase digestion. Due to the unique nature of these oligosaccharides, in that all mannosyl residues are attached by alpha-(1-->2)-linkages beyond the branch points, methylation analysis fails to solve the exact structures beyond Man5. Therefore, we have undertaken this study using 1H nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. In this study, bovine pancreatic ribonuclease B was first reduced and carboxymethylated, and was then deglycosylated by peptide/N-glycosidase F (PNGase F). The released oligosaccharides were fractionated by Bio-Gel P-4 chromatography to give five pools, Man5 through Man9. The structures of the oligosaccharide pools were then studied by laser desorption time of flight mass spectrometry and 1H NMR spectroscopy at 300 MHz. For Man5, Man-A and Man-B are attached in alpha-(1-->3)- and alpha-(1-->6)-linkages to the alpha-(1-->6)-linked Man-4' of the pentasaccharide core structure. For Man6, Man-C is linked alpha-(1-->2) to the alpha-(1-->3)-linked Man-4. Man7 exists as three structural isomers, and has the additional mannosyl residue (Man-D) linked alpha-(1-->2) to Man-A, Man-B, and Man-C is linked alpha-(1-->2) to the alpha-(1-->3)-linked Man-4. Man-7 exists as three structural isomers, with the additional two mannosyl residues linked alpha-(1-->2) to Man-A, Man-B, and Man-C. For each position, Man-A, Man-B, and Man-C, the extent of occupancy by one of the additional alpha-(-->)-linked mannosyl residues was 15, 94, and 91%, respectively. Man9 is a single component, with the three additional mannosyl residues linked alpha-(1-->2) to Man-A, Man-B, and Man-C, respectively. The relative molar proportions of Man5 to Man9 are 57, 31, 4, 7, and 1%, respectively. This report presents for the first time the complete structural characterization of the oligosaccharides from ribonuclease B.

Capillary zone electrophoresis and micellar electrokinetic chromatography of 4-aminobenzonitrile carbohydrate derivatives

Aldoses, ketoses and uronic acids were derivatized successfully within 15 min at a temperature of 90 degrees C by reductive amination with 4-aminobenzonitrile. Subsequently, the derivatives were separated as their borate complexes by capillary zone electrophoresis, using 175 mM borate buffer, pH 10.5, as carrier. The electrophoretic mobilities were determined by the complex stability, which was found to depend on the number of hydroxyl groups on any given carbohydrate derivative, the presence of substituents, and most strongly on the configuration of the vicinal hydroxyl groups at C-3 and C-4 in aldoses and uronic acids, and with regard to ketoses on those at C-4 and C-5. Time of analysis could be reduced considerably by the use of micellar electrokinetic chromatography, which separated 4-aminobenzonitrile sugar derivatives on the basis of their differential partitioning into an electroendosmotically driven aqueous phase and into sodium dodecyl sulfate micelles. Optimum resolution was achieved with a Tris-phosphate buffer, pH 7.5, containing 100 mM of sodium dodecyl sulfate. The method made it possible to resolve several carbohydrates which had not been resolved successfully by means of capillary zone electrophoresis, such as glucose and fructose. Moreover, separation selectivity could be adjusted by varying the capillary temperature. Finally, on-column UV monitoring at 285 nm allowed the detection of glucose with a lower mass detection limit of 1 fmol and a concentration sensitivity of 0.3 microM.

Electrospray ionization mass spectrometry of pyridylaminated oligosaccharide derivatives: sensitivity and in-source fragmentation

Oligosaccharide chains fluorescence-labelled at their reducing end with 2-aminopyridine were analysed by electrospray ionization mass spectrometry (ESIMS). Protonated molecules of complex type oligosaccharides were detectable at a level of 1 pmol. Fragmentation at the glycosidic bonds occurred in the electrospray ion source when the voltage between the capillary nozzle and the first skimmer was elevated, referred to as "in-source fragmentation". Most fragment ions observed had retained the pyridylaminated (PA) site of the molecule and gave significant information on the saccharide sequence. In conjunction with the accumulating data of reversed-phase chromatography of PA oligosaccharides, ESIMS of PA oligosaccharide will be useful as a sensitive method in the structural study of oligosaccharides from various biological sources.

Analysis of carbohydrates in glycoproteins by high-performance liquid chromatography and high-performance capillary electrophoresis

We describe two methods for the analysis of oligosaccharide chains in glycoproteins by high-performance liquid chromatography (HPLC) and high-performance capillary electrophoresis (HPCE). O- and N-glycosidically linked oligosaccharides released from glycoproteins can be identified as their borohydride-reduced forms by anion-exchange HPLC with pulsed amperometric detection. N-Glycosidically linked oligosaccharides can also be analyzed as 2-aminopyridine derivatives by HPCE in direct zone electrophoresis mode in an acidic phosphate buffer and zone electrophoresis mode as borate complexes in an alkaline buffer. We also present a convenient procedure for the analysis of the constituent monosaccharides of these oligosaccharides chains by HPLC based on reversed-phase partition mode as 1-phenyl-3-methyl-5-pyrazolone derivatives.

High-performance capillary electrophoresis of glycoconjugates

Capillary electrophoresis (CE) has recently emerged as a highly promising technique for the analysis and structural study of glycoconjugates. This article reviews the current status of CE and its potential in glycobiology. The separation media suitable for the analysis of monosaccharides, oligosaccharides and very large carbohydrate-based biomolecules are discussed. The detection aspects emphasize chemical derivatization approaches to tagging the glycoconjugates of interest for enhanced response in absorption and fluorescence spectroscopy.

Histochemical analysis of blood group antigens in human sublingual glands and pancreas. An application of high-performance liquid chromatography to estimate the quantity of galactose liberated from tissue sections by alpha-galactosidase digestion

Using immunostaining with monoclonal antibodies (mAbs) from three different sources as well as anti-B lectin, GSAI-B4 staining and alpha-galactosidase digestion, blood group B antigens were localized and analysed in tissue sections of sublingual glands from blood group B and AB individuals. Quantitative analysis of galactose was simultaneously carried out on the supernatant enzyme solution used for treating tissue sections by high-performance liquid chromatography (HPLC). In addition, galactose liberated from the pancreas tissues of blood group B and AB individuals was also estimated by HPLC analysis in order to compare the content of antigens. mAb-B(H079) and GSAI-B4 reacted uniformly with the mucous cells from blood group B and AB secretors. On the other hand, other mAbs-B(B006 and A582) recognized the antigen in a limited number of cells or was even negative in some cases of blood group AB individuals. Only mAb-B(H079) recognized the B antigens in mucous cells from non-secretors. Digestion with alpha-galactosidase resulted in the consistent appearance of H and Le(b) antigens in the mucous cells of all the secretors examined, although the reduction of staining intensity with anti-B reagents was not so marked. Le(y) antigens also appeared in some cases after the enzyme digestion. In non-secretors, Le(b) and Le(y) antigens, but not H antigens, appeared in some mucous cells following enzyme digestion. HPLC analysis of galactose revealed that alpha-galactosidase can specifically liberate the terminal galactose residues of B antigens, and no marked difference was present in the content of liberated galactose from mucous cells of sublingual glands among the individuals investigated (8.5-11.7 nmoles cm-2). No galactose was detected in samples from the sublingual glands of non-secretors, and only a trace amount of galactose was detected in the samples from pancreas tissues. These results suggest that the observed difference in the reactivity of different reagents with each tissue site can be ascribed to both quantitative and qualitative heterogeneity of B antigens.

Structural and functional properties of rhodopsin from rod outer segment disk and plasma membrane

The structural and functional properties of bovine rhodopsin from rod outer segment disk and plasma membranes were compared by high performance liquid chromatography (HPLC), mass spectrometric analyses, and in vitro rhodopsin phosphorylation assays. Disk and plasma membranes separated by a ricin gold-dextran affinity perturbation method were treated with trypsin or cyanogen bromide, and the N-terminal and C-terminal rhodopsin peptides were isolated by immunoaffinity chromatography using antirhodopsin monoclonal antibodies coupled to Sepharose. Reverse phase HPLC chromatograms of the C-terminal and N-terminal peptides from disk and plasma membrane rhodopsin were found to be similar. Mass spectrometric, PicoTag, and hexose analyses of the tryptic 1-16 N-terminal peptides further indicated that the post-translational glycosylation of plasma membrane rhodopsin is identical to that of disk membrane rhodopsin. HPLC analysis of soluble peptides obtained from cyanogen bromide and tryptic digestion of immunoaffinity purified rhodopsin also indicated that no significant differences exist between disk and plasma membrane rhodopsin. Light-induced phosphorylation of rhodopsin in disk and plasma membranes were also compared using in vitro phosphorylation assays. Plasma membrane rhodopsin was found to undergo light-dependent, rhodopsin kinase catalyzed phosphorylation to the same extent as disk membrane rhodopsin. These results indicate that the bulk rhodopsin in rod outer segment plasma membranes appears to be identical to rhodopsin in disk membranes in regard to primary structure, post-translational glycosylation and light-dependent phosphorylation. On this basis, it is unlikely that the sorting of rhodopsin between disk and plasma membranes occurs by a mechanism based on differences in structural properties of rhodopsin.

High-performance capillary electrophoresis of unsaturated oligosaccharides derived from glycosaminoglycans by digestion with chondroitinase ABC as 1-phenyl-3-methyl-5-pyrazolone derivatives

This paper proposes a new method for simultaneous analysis of unsaturated disaccharides derived from glycosaminoglycans by enzymatic digestion with chondroitinase ABC, based on high-performance capillary electrophoresis (HPCE) of their 1-phenyl-3-methyl-5-pyrazolone derivatives. The O-sulphate group is stable in this derivatization, and this method allows reproducible microdetermination of glycosaminoglycans. This paper also demonstrates the applicability of this method to estimation of urinary chondroitin sulphates. Urinary creatinine as an inherent internal standard could also be estimated by HPCE, though in another mode of separation, i.e. ion-exchange electrokinetic chromatography.

Determination of amino sugars and amino acids in glycoconjugates using precolumn derivatization with o-phthalaldehyde

This report examines the RP-HPLC separation of o-phthalaldehyde derivatives of amino acids, amino sugars, and amino sugar alcohols using either 2-mercaptoethanol or 3-mercaptopropionic acid. A method with pmol sensitivity for the analysis of N-acetylamino sugars of glycoconjugates was elaborated. Upon hydrolysis, amino sugars are reduced with borohydride. Automated precolumn derivatization and chromatographic conditions for the resulting hexosaminitols are the same as those used for the analysis of amino acids. The method has been tested with as little as 2 micrograms of bovine fetuin, with a glycopeptide from bromelain and with an oligosaccharide after periodate oxidation.