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PubMed1989

Characterization of oligosaccharides by lectin affinity high-performance liquid chromatography.

Alterations of the oligosaccharide structures of glycoproteins are associated with differentiation, malignant transformation, and expression of the same protein in different cell types. The potential biological importance of oligosaccharides has resulted in a growing need for detailed structural information. When glycoproteins are available in limited quantities and/or bear highly heterogeneous oligosaccharides, characterization of their oligosaccharides is difficult. We have developed an efficient approach for obtaining detailed information about oligosaccharides by determining structural 'fingerprints' using lectin affinity high-performance liquid chromatography.

Chromatography, Affinity↗
PubMed2005

Application of fluorophore-assisted carbohydrate electrophoresis to analysis of disaccharides and oligosaccharides derived from glycosaminoglycans.

Various combinations of fluorescent dyes, polyacrylamide gels, and electrophoresis buffers were tested by fluorophore-assisted carbohydrate electrophoresis (FACE) for the purpose of analyzing sulfated and nonsulfated glycosaminoglycan (GAG) oligosaccharides in which disaccharides and low-molecular weight oligosaccharides were included. A nonionic fluorescent dye was found to be suitable for analyzing sulfated disaccharides derived from sulfated GAGs (e.g., chondroitin sulfate, dermatan sulfate) because sulfated disaccharides themselves had enough anionic potential for electrophoresis. The migration rates of chondroitin sulfate (CS) disaccharides in polyacrylamide gels were affected by the number of sulfate residues and the conformation of each disaccharide. When an anionic fluorescent dye, 8-aminonaphthalene-1,3,6-trisulfonic acid disodium salt (ANTS), was coupled with sulfated GAG oligosaccharides, nearly all of the conjugates migrated at the electrophoretic front due to the added anionic potential. Nonsulfated hyaluronan (HA) oligosaccharides (2-16 saccharides) were subjected to electrophoresis by coupling with a nonionic fluorescent dye, 2-aminoacridone (AMAC), but did not migrate in the order of their molecular size. Especially di-, tetra-, hexa-, and octasaccharides of HA migrated in the reverse order of their molecular size. HA/CS oligosaccharides were able to migrate in the order of their chain lengths by coupling with an anionic fluorescent dye in a nonborate condition.

Aminoacridines↗
PubMed2004

Antioxidant activities of agaro-oligosaccharides with different degrees of polymerization in cell-based system.

The aim of the present study was to evaluate the antioxidant activity of agaro-oligosaccharides with different degrees of polymerizations (DPs) and establish a relationship between the activity and DPs. The attenuate effect of oligosaccharides on 1,1-diphenyl-2-picryl-hydrazyl (DPPH(*)) was initially assessed, and the result indicated that agarohexaose showed the highest scavenging DPPH(*) capability (IC(50)=1.85 mg/ml). Following that, the intracellular antioxidant ability of agaro-oligosacharides was investigated by using the dichlorofluorescein (DCF) assay in human liver cell L-02 system. Different levels of antioxidant activities of agaro-oligosaccharides with various DPs were observed, and their scavenging reactive oxygen species (ROS) capability was associated with the improvement of the cell viability. In these oligosaccharides, agarohexaose possessed the highest scavenging capability, which could reduce 50% of oxidants generated by H(2)O(2) at 1 mg/ml. Furthermore, the antioxidant effect of agarohexaose on the indirect oxidation of cells induced by antimycin A (AA) was also tested. The results showed that agarohexaose could scavenge ROS generated by electron leakage and protect cells against apoptosis induced by ROS. It is concluded that agaro-oligosaccharides are generally considered as novel antioxidants which could protect cell damage caused by reactive oxygen species, especially agarohexaose exhibiting most desirable effects.

Antimycin A↗
PubMed2005

Glycosylation of internal sugar residues of oligosaccharides catalyzed by alpha-galactosidase from Aspergillus fumigatus.

Purified alpha-galactosidase from a thermotolerant fungus Aspergillus fumigatus IMI 385708 was found to catalyze efficiently transgalactosylation reactions using 4-nitrophenyl alpha-D-galactopyranoside as glycosyl donor. Self-transfer reactions with this substrate afforded in low yields several 4-nitrophenyl galactobiosides. Monosaccharides also served as poor glycosyl acceptors. Disaccharides and particularly higher oligosaccharides of alpha-1,4-gluco- (maltooligosaccharides), beta-1,4-gluco- (cellooligosaccharides) and beta-1,4-manno-series were efficiently galactosylated, the latter being the best acceptors that were also doubly galactosylated. With mannooligosaccharides product yields increased with polymerization degree of acceptors reaching 50% at DP of 4-6. Longer oligosaccharide acceptors were galactosylated at internal sugar residues. All galactosyl residues were transferred exclusively to the primary hydroxyl group(s) at C-6 position of oligosaccharide acceptors. This is in accordance with the inability of the enzyme to transfer galactose to beta-1,4-linked xylooligosaccharides. This is the first report of glycosyl transfer reaction to internal sugar residues of oligosaccharides catalyzed by a glycosidase. High affinity to oligosaccharide acceptors also opens a way toward enzymatic glycosylation of polysaccharides, thus modulating their physico-chemical and biological properties.

Aspergillus fumigatus↗
PubMed2006

A remodeling system for the oligosaccharide chains on glycoproteins with microbial endo-beta-N-acetylglucosaminidases.

Endo-M, endo-beta-N-acetylglucosaminidase from Mucor hiemalis, transferred the complex type oligosaccharide of sialoglycopeptide to partially deglycosylated proteins (N-acetylglucosamine-attached proteins), which were prepared by excluding high-mannose type oligosaccharides from glycoproteins with Endo-H, endo-beta-N-acetylglucosaminidase from Streptomyces plicatus. This finding indicated that the high-mannose type oligosaccharides on glycoproteins can be changed to complex type ones by the transglycosylation activity of Endo-M. This is the first report of the establishment of a remodeling system for the different types of oligosaccharides on glycoproteins with microbial endo-beta-N-acetylglucosaminidases having different substrate specificities. Endo-M is a powerful tool for the in vitro synthesis of glycoproteins containing complex type oligosaccharides from glycoproteins produced by yeast.

Glycation End Products, Advanced↗
PubMed2006

Immunomodulation and antitumor activity of kappa-carrageenan oligosaccharides.

The modulation of carrageenan oligosaccharides from Kappaphycus striatum on the immune system in S180-bearing mice was investigated. The mice inoculated with S180 cell suspension were treated p.o. with carrageenan oligosaccharides (50, 100 and 200 microg/g) for 14 days. The effects of carrageenan oligosaccharides on transplantable tumors and macrophage phagocytosis, quantitative hemolysis of sheep red blood cells (QHS), lymphocyte proliferation, the activity of natural killer cells (NK), production of interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) were studied. Carrageenan oligosaccharides could significantly inhibit the growth of transplantable sarcoma S180 and increase macrophage phagocytosis, the form of antibody secreted by spleen cells, spleen lymphocyte proliferation, NK cells activity, serumal IL-2 and TNF-alpha level in S180-bearing mice. Considering all these results, it is suggested that carrageenan oligosaccharides exert their antitumor effect by promoting the immune system.

Animals↗
PubMed2005

Towards understanding the interaction between oligosaccharides and water molecules.

Complex carbohydrates are implicated in many important biological processes, and have a strong interaction with water. This close interplay with molecular water through multiple hydroxyls may be an integral part of their emergent structure and dynamics, as selected during evolution. Using molecular dynamics simulations with explicit water the interactions at the linkages within a variety of oligosaccharides are investigated and contrasted, in order to establish correlations between linkage orientation, sugar epimerization, and water interaction. In particular, interactions at alpha linkages, and between mannose and glucose residues, that are common in oligosaccharides are considered. Sugars joined by alpha linkages at the 2-, 3-, and 6-position were found to interact via a combination of weak hydrogen-bonds and water-bridges, which is dependent on the epimerization state of the sugars. Due to their three-dimensional structure, they are also likely to interact with noncontiguous sugar residues in an oligosaccharide, which can lead to ordered structures through the exclusion of water. On the other hand, beta linkages (to 3- and 4-position) maintain strong hydrogen-bonds, have a limited ability to be involved in water-bridges, and predominantly interact with the directly attached sugars. Therefore, sequences of alpha-linked sugars form compact, branched structures that have conformational flexibility, and beta linkages form extended, relatively rigid structures, suitable for structural molecules, and at the termini of protein bound oligosaccharides. These results provide further tentative ties between chemical structure, water interactions, and the emergent form and function of specific sugars and linkages in oligosaccharides.

Carbohydrate Conformation↗
PubMed2006

A computational study of structure-reactivity relationships in Na-adduct oligosaccharides in collision-induced dissociation reactions.

Elucidating the fragmentation mechanisms in oligosaccharides using theoretical calculations is useful in analyzing the experimentally obtained mass spectra. Semi-empirical and ab initio quantum mechanics calculations were used to study the relationship between the structure and reactivity and the chemical properties of oligosaccharides. In these calculations, sodium-cationized oligosaccharides were investigated to determine Na+ ion affinity at several binding positions; in addition, the dependence of the glycosidic bond cleavage on the Na+ position was examined. The calculated structures reported in this study are directed at interpreting experimentally observed fragment ions, resulting from the cleavage of the glycosidic bonds. The calculated results for oligosaccharides containing between three and five monosaccharide units (27 oligosaccharides) were compared with experimental data generated by matrix-assisted laser-desorption/ionization (MALDI) using a quadrupole ion trap (QIT) with a time-of-flight (TOF) mass spectrometer (MS).

Carbohydrate Sequence↗
PubMed2006

Structural determination of the oligosaccharides in the milk of an Asian elephant (Elephas maximus).

Milk of an Asian elephant (Elephas maximus), collected at 11 days post partum, contained 91 g/L of hexose and 3 g/L of sialic acid. The dominant saccharide in this milk sample was lactose, but it also contained isoglobotriose (Glc(alpha1-3)Gal(beta1-4)Glc) as well as a variety of sialyl oligosaccharides. The sialyl oligosaccharides were separated from neutral saccharides by anion exchange chromatography on DEAE-Sephadex A-50 and successive gel chromatography on Bio Gel P-2. They were purified by high performance liquid chromatography (HPLC) using an Amide-80 column and characterized by 1H-NMR spectroscopy. Their structures were determined to be those of 3'-sialyllactose, 6'-sialyllactose, monofucosyl monosialyl lactose (Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]Glc), sialyl lacto-N-neotetraose c (LST c), galactosyl monosialyl lacto-N-neohexaose, galactosyl monofucosyl monosialyl lacto-N-neohexaose and three novel oligosaccharides as follows: Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc(beta1-3)Gal(beta1-4)Glc, Neu5Ac(alpha2-6)Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)GlcNAc(beta1-3)Gal(beta1-4)Glc, and Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc(beta1-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc(beta1-3)Gal(beta1-4)Glc. The higher oligosaccharides contained only the type II chain (Gal(beta1-4)GlcNAc); this finding differed from previously published data on Asian elephant milk oligosaccharides.

Animals↗
PubMed2005

Oligosaccharide analysis using anion attachment in negative mode electrospray mass spectrometry.

Eleven different anionic species were able to form adducts with neutral oligosaccharides at low cone voltage in negative ion mode electrospray mass spectrometry. Among them, fluoride and acetate have the ability to significantly enhance the absolute abundance of [M - H](-) for neutral oliogosaccharides, which otherwise have low tendencies to deprotonate due to the lack of a highly acidic group. Evidence shows that the source of high abundances of [M - H](-) for neutral oligosaccharides arises from the decomposition of [M + F](-) and [M + Ac](-) with neutral losses of HF and HAc, respectively. The chloride adducts have the best stability among all the adduct species investigated, and chloride adducts consistently appeared in higher abundances relative to [M - H](-). In tandem mass spectrometry (ES-MS/MS) experiments, upon collision induced dissociation (CID), F(-) and Ac(-) adducts gave purely analyte-related product ions, i.e., no detection of the attaching anion and no incorporation of these anions into decomposition products. Cl(-) adducts produced both Cl(-) and analyte-related product ions. For the above three anions, CID of adduct species may be used for structural determination of neutral oligosaccharides because, in each case, structurally-informative fragment ions were produced. In the presence of F(-) and Ac(-), simultaneous detection of acidic and neutral oligosaccharides was achieved, because the problem of the presence of an acidic group that can impede the deprotonation of a neutral oligosaccharide was minimized. The ratio of Cl(-):non-Cl-containing product ions obtained in CID spectra of chloride adducts of disaccharides was used to differentiate anomeric configurations of disaccharides. Density functional theory (DFT) was employed to evaluate the optimized structures of chloride adducts of disaccharides, and it was found that chloride anions favor close contact with the hydrogen from the anomeric hydroxyl group. Multiple hydrogen bonding further stabilizes the chloride adduct.

Anions↗
PubMed2006

Linkage and branch determination of N-linked oligosaccharides using sequential degradation/closed-ring chromophore labeling/negative ion trap mass spectrometry.

A method based on sequential degradation, p-aminobenzoic ethyl ester (ABEE) closed-ring labeling, and negative ion electrospray ionization tandem mass spectrometry is presented for the study of linkage and branch determination for N-linked oligosaccharides. Closed-ring labeling provides greater linkage information than the more popular open-ring reductive amination approach. In addition, after high-performance liquid chromatography (HPLC) separation, closed-ring labeling allows for regeneration of the underivatized oligosaccharide, a requirement for alkaline sequential degradation. The analytical scheme presented here uses HPLC separation of closed-ring labeled oligosaccharides to resolve the mixture into individual forms that undergo subsequent structural analysis by negative ion tandem mass spectrometry. To facilitate complete structural analysis, particularly for larger sugars, the closed-ring labels are removed and the sugars are sequentially degraded by controlled alkaline hydrolysis. It is noteworthy that for sugars containing sialic acid moieties, a protecting group must be used to stabilize sialic acid groups during sequential alkaline degradation. This described approach was applied to two high mannose oligosaccharides M5G2, M6G2 cleaved from the ribonuclease B and a complex oligosaccharide A2 cleaved from transferrin.

4-Aminobenzoic Acid↗
PubMed2005

Oligosaccharide preferences of beta1,4-galactosyltransferase-I: crystal structures of Met340His mutant of human beta1,4-galactosyltransferase-I with a pentasaccharide and trisaccharides of the N-glycan moiety.

beta-1,4-Galactosyltransferase-I (beta4Gal-T1) transfers galactose from UDP-galactose to N-acetylglucosamine (GlcNAc) residues of the branched N-linked oligosaccharide chains of glycoproteins. In an N-linked biantennary oligosaccharide chain, one antenna is attached to the 3-hydroxyl-(1,3-arm), and the other to the 6-hydroxyl-(1,6-arm) group of mannose, which is beta-1,4-linked to an N-linked chitobiose, attached to the aspargine residue of a protein. For a better understanding of the branch specificity of beta4Gal-T1 towards the GlcNAc residues of N-glycans, we have carried out kinetic and crystallographic studies with the wild-type human beta4Gal-T1 (h-beta4Gal-T1) and the mutant Met340His-beta4Gal-T1 (h-M340H-beta4Gal-T1) in complex with a GlcNAc-containing pentasaccharide and several GlcNAc-containing trisaccharides present in N-glycans. The oligosaccharides used were: pentasaccharide GlcNAcbeta1,2-Manalpha1,6 (GlcNAcbeta1,2-Manalpha1,3)Man; the 1,6-arm trisaccharide, GlcNAcbeta1,2-Manalpha1,6-Manbeta-OR (1,2-1,6-arm); the 1,3-arm trisaccharides, GlcNAcbeta1,2-Manalpha1,3-Manbeta-OR (1,2-1,3-arm) and GlcNAcbeta1,4-Manalpha1,3-Manbeta-OR (1,4-1,3-arm); and the trisaccharide GlcNAcbeta1,4-GlcNAcbeta1,4-GlcNAc (chitotriose). With the wild-type h-beta4Gal-T1, the K(m) of 1,2-1,6-arm is approximately tenfold lower than for 1,2-1,3-arm and 1,4-1,3-arm, and 22-fold lower than for chitotriose. Crystal structures of h-M340H-beta4Gal-T1 in complex with the pentasaccharide and various trisaccharides at 1.9-2.0A resolution showed that beta4Gal-T1 is in a closed conformation with the oligosaccharide bound to the enzyme, and the 1,2-1,6-arm trisaccharide makes the maximum number of interactions with the enzyme, which is in concurrence with the lowest K(m) for the trisaccharide. Present studies suggest that beta4Gal-T1 interacts preferentially with the 1,2-1,6-arm trisaccharide rather than with the 1,2-1,3-arm or 1,4-1,3-arm of a bi- or tri-antennary oligosaccharide chain of N-glycan.

Carbohydrate Conformation↗
PubMed2006

In vitro free radical scavenging activities and effect of synthetic oligosaccharides on antioxidant enzymes and lipid peroxidation in aged mice.

In this study we synthesized oligosaccharides using glucose as reactant via a route assisted by microwave irradiation and evaluated their antioxidant activity in vivo and in vitro. The results show that the oligosaccharides exhibited antioxidant activity in vitro as compared to standard antioxidants such as butylated hydroxytoluene (BHT), and alpha-tocopherol. This antioxidant activity depended on concentration and increased with increasing dose of sample. In addition, increased endogenous lipid peroxidation and decreased total antioxidant capacity (TAOC) were observed in aged mice. Thirty-day intraperitoneal administration of the oligosaccharides significantly decreased the lipid peroxidation in a dose-dependent manner. Oligosaccharides treatment increased TAOC and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in all organs tested in aged mice. The present study suggests that the synthetic oligosaccharides possess promising future for their strong free radical scavenging activity. Therefore they can be employed in compensating the decline in TAOC and the activities of antioxidant enzymes and in reducing the risks of lipid peroxidation.

Aging↗
PubMed2004

Human milk oligosaccharides are associated with protection against diarrhea in breast-fed infants.

OBJECTIVE: To determine the association between maternal milk levels of 2-linked fucosylated oligosaccharide and prevention of diarrhea as a result of Campylobacter, caliciviruses, and diarrhea of all causes in breast-fed infants. STUDY DESIGN: Data and banked samples were analyzed from 93 breast-feeding mother-infant pairs who were prospectively studied during 1988-1991 from birth to 2 years with infant feeding and diarrhea data collected weekly; diarrhea was diagnosed by a study physician. Milk samples obtained 1 to 5 weeks postpartum were analyzed for oligosaccharide content. Data were analyzed by Poisson regression. RESULTS: Total 2-linked fucosyloligosaccharide in maternal milk ranged from 0.8 to 20.8 mmol/L (50%-92% of milk oligosaccharide). Moderate-to-severe diarrhea of all causes (n=77 cases) occurred less often (P=.001) in infants whose milk contained high levels of total 2-linked fucosyloligosaccharide as a percent of milk oligosaccharide. Campylobacter diarrhea (n=31 cases) occurred less often (P=.004) in infants whose mother's milk contained high levels of 2'-FL, a specific 2-linked fucosyloligosaccharide, and calicivirus diarrhea (n=16 cases) occurred less often (P=.012) in infants whose mother's milk contained high levels of lacto-N-difucohexaose (LDFH-I), another 2-linked fucosyloligosaccharide. CONCLUSION: This study provides novel evidence suggesting that human milk oligosaccharides are clinically relevant to protection against infant diarrhea.

Adolescent↗
PubMed2005

Fluorophore-assisted carbohydrate electrophoresis: a sensitive and accurate method for the direct analysis of dolichol pyrophosphate-linked oligosaccharides in cell cultures and tissues.

Lipid-linked oligosaccharides (LLOs) such as Glc3Man9GlcNAc2-P-P-dolichol are the precursors of asparagine (N)-linked glycans, which are essential information carriers in many biological systems, and defects in LLO synthesis cause Type I Congenital Disorders of Glycosylation. Due to the low abundance of LLOs and the limitations of the chemical and physical methods previously used to detect them, almost all studies of LLO synthesis have relied upon metabolic labeling of the oligosaccharides with radioactive sugar precursors such as [3H]mannose or [14C]glucosamine. In this article, a procedure is presented for a facile, accurate, and sensitive non-radioactive method for LLO analysis based on fluorophore-assisted carbohydrate electrophoresis (FACE). First, LLOs are extracted and partially purified. Next, oligosaccharides released from LLOs are labeled with negatively charged fluorophores: 8-aminonaphthalene-1,3,6-trisulfonate (ANTS) or 7-amino-1,3-naphthalenedisulfonic acid (ANDS). A specialized form of polyacrylamide gel electrophoresis is then used to resolve and measure ANTS or ANDS labeled oligosaccharides. Finally, the resolved oligosaccharides are detected and quantified by fluorescence imagers using CCD cameras.

Animals↗
PubMed2003

Microanalysis of N-linked oligosaccharides in a glycoprotein by capillary liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry.

We have studied rapid and simple sugar mapping using liquid chromatography/electrospray ionization mass spectrometry (LC/MS) equipped with a graphitized carbon column. The oligosaccharide mixture was separated on the basis of the sequence, branching structure, and linkage, and each oligosaccharide was characterized based on its molecular mass. In this study we demonstrated the usefulness of capillary LC/MS (CapLC/MS) and capillary liquid chromatography/tandem mass spectrometry (CapLC/MS/MS) as sensitive means for accomplishing the structural analysis of oligosaccharides in a low-abundance glycoprotein. The carbohydrate heterogeneity and molecular mass information of each oligosaccharide can be readily obtained from CapLC/MS of a small amount of glycoprotein. CapLC/MS/MS provided b-ion series, which is informative with regard to monosaccharide sequence. Exoglycosidase digestion followed by CapLC/MS elucidated a carbohydrate residue linkage. Using this method, we characterized N-linked oligosaccharides in hepatocyte growth factor produced in mouse myeloma NS0 cells as the complex-type bi-, tri-, and tetraantennary terminated with N-glycolylneuraminic acids and alpha-linked galactose residues. Sugar mapping with CapLC/MS and CapLC/MS/MS is useful for monitoring glycosylation patterns and for structural analysis of carbohydrates in a low-abundance glycoprotein and thus will become a powerful tool in biological, pharmaceutical, and clinical studies.

Animals↗
PubMed1986

Purification of oligosaccharides having a free reducing-end from glycopeptide sources.

A hydrazinolysis-N-reacetylation procedure, modified by the inclusion of a mild acid-hydrolysis step after N-acetylation, was used to prepare, in overall yields of 60-70%, pure oligosaccharides containing a reducing D-GlcNAc residue from glycopeptide sources. Three types of asparagine-linked glycopeptides were treated: a high-mannose type, a complex-type not containing sialic acid, and a complex-type containing sialic acid, linked both alpha-(2----3) and alpha-(2----6) to beta-D-Galp residues. After the hydrazinolysis-N-reacetylation procedure, there was often contamination of the reducing oligosaccharides with glycopeptide that remained intact through the procedure, as well as minor oligosaccharide products, altered in the nature of the residue at the reducing end. Oligosaccharides having a reducing D-GlcNAc residue were purified by standard liquid chromatography and high-pressure liquid chromatography (l.c.) 360-MHz 1H-n.m.r. was valuable in establishing common structural reporter signals which enabled major products to be identified at stages during the production of free reducing oligosaccharides, and their purity to be assessed.

Animals↗
PubMed2001

Structural analyses of two arabinose containing oligosaccharides derived from olive fruit xyloglucan: XXSG and XLSG.

Xyloglucan oligosaccharides were prepared by endo-(1-->4)-beta-D-glucanase digestion of alkali-extractable xyloglucan from olive fruit and purified by a combination of gel-permeation (Bio-Gel P-2) chromatography and high-performance anion-exchange chromatography. The two most abundant oligosaccharides were converted to the corresponding oligoglycosyl alditols by borohydride reduction and structurally characterised by NMR spectroscopy and post-source decay (PSD) fragment analysis of matrix-assisted laserinduced desorption/ionisation time-of-flight (MALDI-TOF) mass spectra. The results revealed that olive fruit xyloglucan is mainly built from two novel oligosaccharides: XXSG and XLSG. The structure of the oligosaccharides confirmed the presence of a specific xyloglucan in olive fruit with alpha-L-Araf-(1-->2)-alpha-D-Xylp sidechains as was suggested previously. The presence of such sidechains is a common feature of xyloglucans with an XXGG core produced by solanaceous plants but has not been demonstrated for other dicotyledonous plants, which have in general an XXXG core. Direct treatment of cell wall material from olive fruit with pectin degrading enzymes in combination with endo-(1-->4)-beta-D-glucanase revealed that some of the arabinose residues of the oligosaccharides XXSG and XLSG are substituted with either 1 or 2 O-acetyl groups.

Arabinose↗