A novel {beta}-galactosidase gene isolated from the bacterium Xanthomonas manihotis exhibits strong homology to several eukaryotic {beta}-galactosidases

The gene encoding a ß-galactosidase from Xanthomonasmanihotis was cloned into Escherichia coli. The gene resideson a 2.4 kb DNA fragment which was isolated from a partial Sau3Alibrary in the cloning vector pUC19 using 5-bromo-4-chloro-3-indolyl-ß-D-galactopyranoside(X-gal) as the selection. The enzyme produced by the clone hasa specificity for ß1-3->ß1-4-linked galactose.The nucleotide sequence of the gene was determined. The deducedprotein sequence contained 597 amino acids yielding a monomericmolecular mass of 66 kDa. The cloned ß-galactosidaseshowed no similarity to any known prokaryotic ß-galactosidase.However, extensive similarity was observed with eukaryotic ß-galactosidasesfrom animals, plants and fungi. The strongest similarity waswith the ß-galactosidases found hi the human and mouselysosomes (42 and 41% identity, respectively). Alignment ofthe X.manihotis and eukaryotic ß-galactosidase sequencesrevealed seven highly conserved domains common to each protein.Additionally, Domain 1 in X.manihotis showed similarity to regionswithin catalytic domains from seven xylanases and cellulasesbelonging to family 10 of glucosyl hydrolases. A region spanningDomain 2 showed similarity to the catalytic domain of endo ß1-3glucanases from tobacco and barley. cellulase ß-galactosidase G_M$$$gangliosidosis Morquio B syndrome Xanthomonas     

Alterations of O-glycan biosynthesis in human colon cancer tissues

Human colon cancer is associated with antigenic and structuralchanges in mucin-type carbohydrate chains (O-glycans). To elucidatethe control of the biosynthesis of these O-glycans in coloncancer, we have studied glycosyltransferase and sulphotransferaseactivities involved in the assembly of elongated O-glycan structures.We analysed homogenates prepared from cancer tissue, adjacentnormal and distal normal tissue from 20 patients. Several transferaseactivities showed pronounced changes in cancer tissue. The changescorrelate with previous findings of a loss of O-glycans in cancermucins, but did not always correlate with levels of Tn, sialyl-Tn,T and Le^x antigens in homogenates or with the differentiationstatus and Duke's stages of the cancer tissue or the patient'sblood type, sex and age. UDP-GlcNAc: Gal NAc-R ß3-N-acetylglucosaminyltransferase(where GlcNAc is N-acetyl-D-glucosamine and GalNAc is N-acetyl-D-galactosamine)synthesizing O-glycan core 3, GlcNAcß1-3GalNAc-, CMP-sialicacid: GalNAc-peptide     

Carcinoma autoantigens T and Tn and their cleavage products interact with Gal/GalNAc-specific receptors on rat Kupffer cells and hepatocytes

We studied interactions of isolated Thomsen-Friedenreich (T)- and Tn-specific glycoproteins with the Gal/GalNAc-specific receptors on rat Kupffer cells and compared them to those with rat hepatocytes. Immunoreactive T and Tn are specific pancarcinoma epitopes. Electron microscopy of gold-labelled T and Tn antigens revealed their specific binding to Kupffer cells, followed by their uptake via the coated pit/vesicle pathway of receptor-mediated endocytosis. Preincubation of Kupffer cells with GalNAc and GalNAc-BSA, but not GlcNAc or GlcNAc-BSA specifically inhibited binding of the T and Tn glycoproteins. Desialylated, isologous erythrocytes (T RBC) are known to bind to the Gal/GalNAc receptors of rat Kupffer cells and hepatocytes. This attachment was specifically inhibited by T and Tn in a concentration-dependent manner: 50% T RBC-Kupffer cell contacts were inhibited at 8.5.10(-6) mM T and 8.5.10(-5) mM Tn antigen concentrations, respectively. The corresponding figures for hepatocytes were 6.10(-6) mM T and 1.2.10(-6) mM Tn antigen. Amino-terminal cleavage products of the T glycoprotein, possessing clusters terminating in non-reducing Gal/GalNAc, inhibited T RBC binding to Kupffer cells and hepatocytes usually at 10(-2) to 10(-5) mM concentrations, whereas GalNAc, galactose and galactose glycosides inhibited at millimolar concentrations. Galactose-unrelated carbohydrates were inactive at concentrations greater than or equal to 50 mM.     

AMD3100 conjugates as components of targeted nonviral gene delivery systems: synthesis and in vitro transfection efficiency of CXCR4-expressing cells

We describe the synthesis of a series of AMD3100-lipid and AMD3100-polycationic conjugates which were used as components of targeted lipoplexes (in conjunction with (poly)cationic lipids) and polyplexes, respectively, for mediating specific gene transfer into cells expressing CXCR4 which displays a high affinity for AMD3100. Transfection studies were investigated with suspension CXCR4(+) human lymphoma Jurkat cells and with adherent CXCR4(-) human glioblastoma T98G and human lung carcinoma A549 cells lines in order to demonstrate a receptor-mediated endocytosis pathway and to minimize nonspecific transfection pathways. Altogether, our results show that polyplexes formulated with AMD-labeled polymers constitute, under certain conditions, specific gene transfer systems into suspension CXCR4(+) Jurkat cells. This is more particularly the case when the nonspecific transfection pathways are minimized (i.e. for N/P 相似文献   

Expression of the Tn antigen on T-lymphoid cell line Jurkat.

Expression of the Tn antigen on a T-lymphoid cell line, Jurkat, was investigated using an anti-Tn monoclonal antibody, MLS 128. Immunoprecipitation or immunoaffinity chromatography of a lysate of Jurkat cells led to the isolation of a 120 kDa glycoprotein carrying the Tn antigen. This glycoprotein and leukosialin (CD43) were indistinguishable on SDS-PAGE and as to immunoreactivity with MLS 128. Leukosialin from an erythroid cell line, K562, exhibited no reactivity with MLS 128 despite that this leukosialin has several GalNAc alpha-Ser(Thr) structures. Pulse-chase experiments with the Jurkat leukosialin showed that newly synthesized leukosialin acquired the antigenecity after a lag of about 30 min, whereas incorporation of GalNAc into the leukosialin occurred earlier. These results indicate that the Tn antigen is expressed on leukosialin and that its epitopic structure is more complex than GalNAc alpha-Ser(Thr).     

Comparative Studies of Acid Glycosidases from Three Legumes

The major isoenzymes of -mannosidase (EC 3.2.1.24 [EC] ) and ß-galactosidase(ECf 3.2.1.23 [EC] ) have been separated from cotyledons of gardenpea, Pisum sativum L. (Vicieae), chick pea, Cicer arietinumL. (Cicereae), and cowpea, Vigna unguiculata (L.) Walp. (Phaseoleae).Some of their properties have been determined, including pHoptima, K_m values for p-nitrophenyl glycosidc substrates, andthe effects of several inhibitors. Swainsonine, an indolizidinealkaloid, was the most effective inhibitor of mannosidase 1,with I₃₀ values of 5.6 x 10^–8 M (cowpea), 1x 10^–7M (chick pea) and 2.9 x 19^–7 M (pea). The most effectiveinhibitor of ß-galactosidase 2 from all sources wasD-galactonic acid-1,4-lactonwe (-lactone), with K_i values rangingbetween 3.0 and 3.9x 10^–3 M. An inhibitor of the E. coliß-galactosidose, p-aminophenyl thio-ß-D-galactopyranoside,did not inhibit any of the legume ß-galctosidases;rather it enhanced the activites of the enzymes from chick peaand cowpea cotyledons. Etiolated hull and seed tissues frompea pods developing in darkness contained similar acid glycosidaseactivities to normal green tissues, thus the chloroplast isan unlikely location for ß-galactosidase 2. The majorß-galactosidasesdetected with an indigogenic substrate (5-bromo-4-chloro-3-indoxyl-ß-D-galactopyranoside)following gel electrophoresis of extracts from pea hull, seedcoats and cotyledons appeared to be different from ß-galactosidase2. Acid glycosidase, cotyledon, isoenzyme, -lactone, legume, swainsonine     

Flexibility in the donor substrate specificity of {beta} 1,4-galactosyltransferase: application in the synthesis of complex carbohydrates

Biosynthetically, bovine N-acetylglucosainine ß 1,4-galacto-syltransferase(GalT) catalyses the transfer of galactosyl residues from UDP-Galto the 4-position of GlcNAc units, resulting in the productionof N-acetyllactosamine sequences. UDP-Glc and UDP-GalNAc werealso found to act as donors for this enzyme, allowing the preparationof ßGlc(14)-ßGlcNAc and ßGalNAc(14)ßGlcNActerminating structures on the milligram scale. GalT could thusbe used to add ßGalNAc to ßGlcNAc(12)Manterminating structures, converting them to the ßGalNAc(14)ßGlcNAc(12)Mansequences found on glycoprotein hormones. GalT did not transferGlcNAc residues from UDP-GlcNAc, but it could utilize UDP-GlcNH₂as a donor. Synthesis of ßGlcNAc(14)ßGlcNAcsequences could therefore be accomplished by transfer of GlcNH₂from its UDP derivative, followed by N-acetylation of the productamino-disaccharide using acetic anhydride in methanol. The productsof the enzymatic reactions were characterized by ¹H-NMR-spectroscopyand fast-atom bombardment mass spectrometry. This work expandsthe scope of the combined chemical-enzymatic synthesis of complexcarbohydrates, using glycosyltrans-ferases, to the productionof oligosaccharides different from those for which these enzymeswere designed. These unnatural reactions should find applicationin glycoprotein and glycolipid remodelling. galactosyltransferase chemica1-enzymatic synthesis of oligosaccharides oligosaccharide analogues sugar-nucleotide analogues carbohydrate remodelling     

Two different glycosyltransferase defects that result in GalNAc{alpha}-O-peptide (Tn) expression

This study shows for the first time that different glycosyltransferasedefects in the biosynthesis of O-linked oligosaccharides giverise to the same GalNAc-O-Ser/Thr determinant on Tn erythrocytesand colorectal carcinoma cells. The O-linked oligosaccharidesisolated from the glycophorins of Tn erythrocytes containedpredominantly -Nacetylgalactosamine-O-Ser/Thr (Tn antigen) andsialyl-Tn. A marked reduction in normal sialylated oligosaccharideswas also observed. Monoclonal antibody BRIC 111 raised againstTn erythrocytes reacted with both Tn erythrocytes and colorectalcarcinoma tissues. Weak staining was detected in the supranucleararea and at the surface membranes in normal colorectal cells,but was absent from goblet cell vesicles. An increase in supranuclearstaining over controls was found in tumour tissue and in themajority of resection margin specimens. The highest levels ofstaining were present in transitional mucosa, adjacent to thetumours where goblet vesicles were also positive. Glycosylationdefects in the same patients were further studied by determinationof the activity of glycosyltransferases in mucosal tissue fromcontrol and cancer patients. The reduction in or loss of ß1-3 N-acetylglucosaminyl transferase activity to GalNAc-peptidein asialo-ovine submaxillary gland glycoprotein was detectedby direct assay and by isolation of the oligosaccharides fromthe incubation products. No differences in N-acetylglucosaminyl-,galactosyl- or sialyl-transfer to Galß1-3GaINAc inantifreeze glycoprotein or in sialyl transferase to asialo-ovinesubmaxillary gland glycoprotein were detected. Our study showsthat the GalNAc-O-Ser/Thr determinant on Tn erythrocytes andin colorectal carcinoma results from different glycosyltransferasedefects in separate biosynthetic pathways for haematopoieticand epithelial tissues. -N-Acetylgalactosamine-O-Ser Thr colon cancer erythrocyte O-glycosylation glycosyltransfer Tn     

The unusual tetrasaccharide sequence GlcA{beta}-3GalNAc(4-sulfate)({beta}1-4GlcA(2-sulfate){beta}1-3GalNAc(6-sulfate) found in the hexasaccharides prepared by testicular hyaluronidase digestion of shark cartilage chondroitin sulfate D

Eight hexasaccharide fractions were isolated from commercialshark cartilage chondroitin sulfate D by means of gel nitrationchromatography and HPLC on an amine-bound silica column afterexhaustive digestion with sheep testicular hyaluronidase. Capillaryelectrophoresis of the enzymatic digests as well as one- andtwo-dimensional 500 MHz ¹H-NMR spectroscopy demonstrated thatthese hexasaccharides share the common core saccharide structureGlcAß1-3GalNAcß1-4GlcAß1-3GalNAcß1-4GlcAß1-3GalNAcwith three, four, or five sulfate groups in different combinations.Six structures had the same sulfation profiles as those of theunsaturated hexasaccharides isolated from the same source afterdigestion with chondroitinase ABC (Sugahara et al., Eur. J.Biochem., 293, 871–880, 1996) and the other two have notbeen reported so far. In the new components, a D disaccharideunit, GlcA(2-sulfate)ß1-3GalNAc(6-sulfate), characteristicof chondroitin sulfate D was arranged on the reducing side ofan A disaccharide unit, GlcAß1-3GalNAc(4-sulfate),forming an unusual A-D tetrasaccharide sequence, GlcAß1-3GalNAc(4-sulfate)-4GlcA(2-sulfate)ß1-3GaINAc(6-sulfate)which is known to be recognized by the monoclonal antibody MO225.These findings support the notion that the tetrasaccharide sequence,GlcAß1-3GalNAc(4-sulfate)ß1-4GlcAß1-3GalNAc(6-sulfate)is included in the acceptor site of a hitherto unreported 2-O-sulfotransferaseresponsible for its synthesis. The sulfated hexasaccharidesisolated in this study will be useful as authentic oligosaccharideprobes and enzyme substrates in studies of sulfated glycosaminogly-cans. sulfated hexasaccharides chondroitin sulfate D hyaluronidase ¹ H-NMR     

Analysis of Tn antigenicity with a panel of new IgM and IgG1 monoclonal antibodies raised against leukemic cells

CD175 or Tn antigen is a carbohydrate moiety of N-acetylgalactosamine (GalNAc)α1-O- linked to the residue of amino acid serine or threonine in a polypeptide chain. Despite the chemical simplicity of the Tn antigen, its antigenic structure is considered to be complex and the clear determinants of Tn antigenicity remain poorly understood. As a consequence, a broad variety of anti-Tn monoclonal antibodies (mAbs) have been generated. To further investigate the nature and complexity of the Tn antigen, we generated seven different anti-Tn mAbs of IgM and IgG classes raised against human Jurkat T cells, which are Tn-positive due to the low activity of T-synthase and mutation in specific chaperone Cosmc. The binding analysis of anti-Tn mAbs with the array of synthetic saccharides, glycopeptides and O-glycoproteins revealed unexpected differences in specificities of anti-Tn mAbs. IgM mAbs bound the terminal GalNAc residue of the Tn antigen irrespective of the peptide context or with low selectivity to the glycoproteins. In contrast, IgG mAbs recognized the Tn antigen in the context of a specific peptide motif. Particularly, JA3 mAb reacted to the GSPP or GSPAPP, and JA5 mAb recognized specifically the GSP motif (glycosylation sites are underlined). The major O-glycan carrier proteins CD43 and CD162 and isoforms of CD45 expressed on Jurkat cells were precipitated by anti-Tn mAbs with different affinities. In summary, our data suggest that Tn antigen-Ab binding capacity is determined by the peptide context of the Tn antigen, antigenic specificity of the Ab and class of the immunoglobulin. The newly generated anti-Tn IgG mAbs with the strong specificity to glycoprotein CD43 can be particularly interesting for the application in leukemia diagnostics and therapy.     

Human T Cell Activation Results in Extracellular Signal-regulated Kinase (ERK)-Calcineurin-dependent Exposure of Tn Antigen on the Cell Surface and Binding of the Macrophage Galactose-type Lectin (MGL)

The C-type lectin macrophage galactose-type lectin (MGL) exerts an immunosuppressive role reflected by its interaction with terminal GalNAc moieties, such as the Tn antigen, on CD45 of effector T cells, thereby down-regulating T cell receptor signaling, cytokine responses, and induction of T cell death. Here, we provide evidence for the pathways that control the specific expression of GalNAc moieties on human CD4⁺ T cells. GalNAc epitopes were readily detectable on the cell surface after T cell activation and required de novo protein synthesis. Expression of GalNAc-containing MGL ligands was completely dependent on PKC and did not involve NF-κB. Instead, activation of the downstream ERK MAPK pathway led to decreased mRNA levels and activity of the core 1 β3GalT enzyme and its chaperone Cosmc, favoring the expression of Tn antigen. In conclusion, expression of GalNAc moieties mirrors the T cell activation status, and thus only highly stimulated T cells are prone to the suppressive action of MGL.     

Characterization of serum {beta}-glucuronyltransferase involved in chondroitin sulfate biosynthesis

We studied a glucuronyltransferase involved in chondroitin sulfate(CS) biosynthesis in a preparation obtained from fetal bovineserum by heparin-Sepharose affinity chromatography. This enzymetransferred GlcA from UDP-GlcA to the nonreducing GalNAc residuesof polymeric chondroitin. It required Mn²⁺ for maximal activityand showed a sharp pH optimum between pH 5.5 and 6.0. The apparentKm value of the glucuronyltransferase for UDP-GlcA was 51 µM.The specificity was investigated using structurally definedacceptor substrates, which consisted of chemically synthesizedtri-, penta-, and heptasaccharide-serines and various odd-numberedoligosaccharides with a GalNAc residue at the nonreducing terminus,prepared from chondroitin and CS by chondroitinase ABC digestionfollowed by mercuric acetate treatment. The enzyme utilizeda heptasaccharide-serine GalNAcß1-4GlcAß1-3GalNAcß1-4GlcAß1-3Galß1-3Galß1-4Xylß1-O-Serand a pentasaccharide-serine GalNAcß 4GlcAß1-3Galß1-3Galß1-4Xylß1-O-Seras acceptors. In contrast, neither a trisaccharide-serine Galß1-3Galß1-4Xylß1-O-Sernor an     

Monoclonal antibodies toward different Tn-amino acid backbones display distinct recognition patterns on human cancer cells. Implications for effective immuno-targeting of cancer

The Tn antigen (GalNAcα-O-Ser/Thr) is a well-established tumor-associated marker which represents a good target for the design of anti-tumor vaccines. Several studies have established that the binding of some anti-Tn antibodies could be affected by the density of Tn determinant or/and by the amino acid residues neighboring O-glycosylation sites. In the present study, using synthetic Tn-based vaccines, we have generated a panel of anti-Tn monoclonal antibodies. Analysis of their binding to various synthetic glycopeptides, modifying the amino acid carrier of the GalNAc(*) (Ser* vs Thr*), showed subtle differences in their fine specificities. We found that the recognition of these glycopeptides by some of these MAbs was strongly affected by the Tn backbone, such as a S*S*S* specific MAb (15G9) which failed to recognize a S*T*T* or a T*T*T* structure. Different binding patterns of these antibodies were also observed in FACS and Western blot analysis using three human cancer cell lines (MCF-7, LS174T and Jurkat). Importantly, an immunohistochemical analysis of human tumors (72 breast cancer and 44 colon cancer) showed the existence of different recognition profiles among the five antibodies evaluated, demonstrating that the aglyconic part of the Tn structure (Ser vs Thr) plays a key role in the anti-Tn specificity for breast and colon cancer detection. This new structural feature of the Tn antigen could be of important clinical value, notably due to the increasing interest of this antigen in anticancer vaccine design as well as for the development of anti-Tn antibodies for in vivo diagnostic and therapeutic strategies.     

Synthesis of O-glycan core 3: Characterization of UDP-GlcNAc: GalNAc-R {beta}3-N-acetyl-glucosaminyltransferase activity from colonic mucosal tissues and lack of the activity in human cancer cell lines

UDP-GlcNAc: GalNAc-R ß3-GlcNAc-transferase (core 3ß3-GlcNAc-T, where GlcNAc is N-acetyl-D-glucosamine,GalNAc is N-acetyl-D-galactosamine and T is transferase) isexpressed in a tissue-specific fashion and is high in normalcolonic tissue, but downregulated in colon cancer. To furtherstudy the control of this enzyme, we examined the activity inpig, rat and human colonic tissues, and several human cancercell lines. The enzyme was difficult to solubilize by detergentsand was extremely unstable in the solubilized form. Using syntheticderivatives of the GalNAc-R substrate, we showed that the specificityof the enzyme in normal rat and human colonic mucosa requiresall the substituents of the GalNAc-sugar ring of substratesfor maximal activity. Core 3 ß3-GlcNAc-T was significantlyinfluenced by the structure of the aglycon group. None of theinactive substrate derivatives could inhibit the activity. N-Iodoacetamido-galactosamine     

Relation of Glycosidases to Amaryllis vittata Pollen Tube Growth

The role of glycosidases activity in the regulation of pollentube extension in Amaryllis vittata during in vitro germinationwas investigated. No significant change in the enzyme activities(-glucosidase, -galactosidase, rß-glucosidase andrß-galactosidase) at different stages of tube growthwas found. No increase in patent rß-glucosidase activityassayed directly in a suspension of intact germinating pollenwas observed. The results are discussed in the light of thedifferential role of wall-bound glycosidases in cells showingoverall surface growth and tip growth i.e., pollen tubes. (Received February 4, 1981; Accepted June 5, 1981)     

{beta}1,4-Galactosyltransferase activity in B cells detected using a simple ELISA-based assay

Lymphocytic ß1,4-galactosyltransferase (ß1,4-GalTase,EC 2.4.1.38 [EC] ) activity was measured in B cells using a neoglycoprotein,N-acetylglucosamine-phenylisothlocyanate-bovine serum albumin(GlcNAc-pITC-BSA), as an acceptor substrate in a novel enzyme-linkedimmunosorbent assay (ELISA)-based method. This assay provedto be much simpler to use than the lengthy and expensive radiochemicalassays commonly used, and has the additional advantage thatit specifically detects the enzyme mediating transfer via theGalß1,4GlcNAc linkage. A F(ab')₂ antibody againstGalTase was able to specifically inhibit the reaction. Greatersensitivity for ß1,4-GalTase activity was obtainedusing GlcNAc-pITC-BSA as an acceptor substrate rather than ovalbumin.Low levels of ß-galactosidase activity were detectablein lymphocyte cell lysates at acidic pH, although such activitywas not detectable at the neutral pH used in the ß1,4-GalTaseactivity assay. Using this assay with the GlcNAc-pITC-BSA acceptor,similar ß1,4-GalTase activities were observed in CD19⁺B cells from patients with rheumatoid arthritis (RA) to thoseseen in normal control individuals. ELISA ß1,4-galactosyltransferase lymphocyte neoglycoprotein radiochemical     

Targeted transfection of human hepatoma cells with a combination of lipospermine and neo-galactolipids

Abstract

Optimal in vitro gene delivery with (poly)cationic amphiphiles requires an excess of cationic charges with respect to DNA phosphates. We have developed targeted transfection systems based on electrically neutral lipospermine/DNA particles, to which synthetic tri-antennary galactose ligands were conjugated to provide an interaction with cells, such as HepG2 cells, that express Gal/GalNAc receptors at their surface. Transfection, which was cell specific, increases ? 1000-fold with 25% neogalactolipid, i.e. approaching the value observed with optimized positively charged transfection complexes. Unexpectedly, neutral particles containing thiol-reactive phospholipids, were also efficient gene delivery systems, although non cell specific.     

Production and secretion of {alpha}-galactosidase and endo-{beta}-mannanase by carob (Ceratonia siliqua L.) endosperm protoplasts

Viable protoplasts were isolated for the first time from maturecarob (Ceratonia siliqua L.) endosperm tissue. After 5 d ofincubation 75% of the protoplasts were viable. During incubationthey underwent vacuolation and produced the carob endospermhydrolases, agalactosidase and endo-ß-mannanase, whichwere secreted in the incubation medium. The secretion of bothenzymes were under Ca²⁺ control. Many characteristics of -galactosidaseand endo-ß-mannanase production by protoplasts werethe same as those of whole endosperms: their production didnot require any hormonal signal and was inhibited in the presenceof ABA or the leachate from the carob endosperm/seed coat. Moderatewater stress (—2.0 MPa) neither affected the activityof these hydrolases nor their secretion by endosperm protoplast.However, when the osmoticum of protoplast incubation mediumwas higher, the production and secretion of both hydrolaseswere reduced. Comparison of the hydrolases activities in theincubation media of leached carob endosperms, which were incubatedunder normal and water stress (—1.5 MPa) conditions, withthe activities of the protoplast-secreted hydrolases indicatedthat (i) carob endosperm cell wall acts as a barrier for thesecreted enzymes and (ii) that water stress reduces the cellwall porosity of the carob endosperm cells, and thus the releaseof the secreted -galactosidase and endo-ß-mannanaseis inhibited. The isolation of carob endosperm protoplasts offersa potent experimental system for the study of aspects of endospermcell physiology, such as enzyme secretion Key words: Abscisic acid, carob endosperm, Ceratonia siliqua L, endo-ß-mannanase, -galactosidase, leachate, protoplasts, water stress     

Characterization of a novel mucin sulphotransferase activity synthesizing sulphated O-glycan core 1, 3-sulphate-Gal{beta}1-3GalNAc{alpha}-R

A novel sulphotransferase (sulpho-T) activity from rat colonicmucosa was characterized using O-glycan core 1 substrate, Galß1-3GalNAc