How a plant lectin recognizes high mannose oligosaccharides

The crystal structure of Pterocarpus angolensis seed lectin is presented in complex with a series of high mannose (Man) oligosaccharides ranging from Man-5 to Man-9. Despite that several of the nine Man residues of Man-9 have the potential to bind in the monosaccharide-binding site, all oligomannoses are bound in the same unique way, employing the tetrasaccharide sequence Manalpha(1-2)Manalpha(1-6)[Manalpha(1-3)]Manalpha(1-. Isothermal titration calorimetry titration experiments using Man-5, Man-9, and the Man-9-containing glycoprotein soybean (Glycine max) agglutinin as ligands confirm the monovalence of Man-9 and show a 4-times higher affinity for Man-9 when it is presented to P. angolensis seed lectin in a glycoprotein context.     

A lectin from the lichenized Basidiomycete Dictyonema glabratum

A lectin with hemagglutinating activity has been isolated from an aqueous extract of the symbiotic phenotype of Dictyonema glabratum and its cyanobacterial photobiont Scytonema sp. The purified lectin had a pI of 6.8 and its molecular mass was investigated by electrospray ionization mass spectrometry, gel filtration and SDS-PAGE, which indicated its native conformation as a dimer formed by two identical subunits of 16540 Da. The lectin is a glycoprotein with a low degree of glycosylation, containing galactose, xylose, glucose and mannose as neutral monosaccharides, in addition to glucosamine, which could indicate both N - and O -linkages. Amino acid analysis showed the predominance of nonpolar residues such as phenylalanine. Agglutination of human erythrocytes required divalent cations, which is affected by addition of EDTA. The lectin was more stable at 30 °C or less for at least 1 h and between pH 5.0 and 7.0. Among the various compounds tested for hemagglutination inhibition, N -acetylgalactosamine was the most active. The potential role of this lectin in recognition of the compatible cyanobacterial photobiont is discussed.     

Occurrence of natural lectin with bacterial agglutination property in the serum of lepidopteran pest,Parasa lepida

Insects depend on lectins for non‐self recognition and clearance of invading pathogens. Naturally occurring lectin showing specificity for galactose was purified from the serum of lepidopteran pest Parasa lepida by affinity chromatography using Sepharose 6B coupled with galactose as a gel matrix. Preliminary studies on crude serum agglutinin revealed that the agglutinin molecule showed varying degrees of specificity to avian and mammalian red blood cells tested. Among them, the highest titer of 128 was recorded against rabbit red blood cell type. The agglutinin molecule in the crude serum was stable up to 60°C and at pH between 6 and 9. Also, the hemagglutinating activity was neither dependent on divalent cations nor sensitive to ethylenediaminetetraacetic acid treatment. Galactose inhibited the hemagglutinating activity at minimum inhibitory concentration of 12.5 mM and hence it was used as a ligand for affinity chromatography. Native polyacrylamide gel electrophoresis analysis revealed a single band and the molecular weight of the lectin was found to be approximately 90 kDa. Bacterial agglutination activity of the purified lectin with two significant toxin bacteria, namely Salmonella typhi and Bacillus thuringiensis, was observed.     

A New Bacterial Agglutinin from Soybean: I. ISOLATION, PARTIAL PURIFICATION, AND CHARACTERIZATION

A new bacterial agglutinin was isolated from seeds of the soybean cultivar Clark. Purification was carried out by ammonium sulfate precipitation and ion-exchange chromatography. The agglutinin is a heat-labile glycoprotein most active at pH 4.0. Addition of Ca²⁺, Mn²⁺ and Mg²⁺ did not enhance the agglutinating activity of this glycoprotein. Gel electrophoresis in the presence of sodium dodecyl sulfate showed that the agglutinin is composed of two subunits of approximately 50,000 daltons each. In the undissociated state, it agglutinates Xanthomonas phaseoli var. sojensis, the causal agent of bacterial pustule disease of soybean, at concentrations as low as 10 micrograms protein per milliliter but has no hemagglutinating activity. The agglutinin could be distinguished from previously reported soybean lectins on the basis of solubility in ammonium sulfate, lack of hemagglutinating activity, molecular weight, hapten specificity, and immunological determinants.     

Influence of lectins on the binding of 125I-labeled EGF to human fibroblasts.

Lectins that interact with mannose (concanavalin A), galactose (ricin, abrin), or N-acetylglucosamine (wheat germ agglutinin) block ¹²⁵I-labeled EGF binding to the surface of cultured human fibroblasts at 37° or 5°. Lectins specific for fucose or N-acetylgalactosamine, soybean agglutinin or gorse lectin, respectively, do not interfere with growth factor binding. The inhibition of ¹²⁵I-labeled EGF binding by concanavalin A at 37° or 5° could be reversed rapidly by the addition of α-methyl mannoside. The results suggest that the fibroblast membrane receptor for EGF is, or is closely associated with, a glycoprotein or glycolipid that contains mannose, galactose and N-acetylglucosamine residues.     

Isolation and characterization of mosquito cell membrane glycoproteins

Plasma membranes have been purified from an established cell line, Mos 20A of Aedes aegypti, and analysed for glycoprotein and polypeptide constituents by isoelectric focusing and sodium dodecyl sulphate polyacrylamide gel electrophoresis. A major glycoprotein of molecular weight 110 000 carrying binding sites for concanavalin A and soybean agglutinin has been purified to homogeneity. Although located on the cell surface, the 110 kdalton glycoprotein is not labelled by lactoperoxidase-catalysed radioactive iodination of whole cells. Analysis indicates the presence of N-glycans, containing on average nine mannose residues, and the N-acetylglucosaminyl-β1,4-N-acetylglucosamine sequence. In addition, O-glycosidically linked N-acetylgalactosamine residues are present.     

Purification and carbohydrate-binding specificities of a blood type B binding lectin from hemolymph of a crab (Charybdis japonica)

A blood type B binding lectin (CJA-B) was isolated from the hemolymph of the crab Charybdis japonica by affinity chromatography on Sephadex G-200. The molecular mass of the native lectin was determined to be 300 kDa by gradient polyacrylamide gel electrophoresis under nondenaturing conditions. On SDS-polyacrylamide gel electrophoresis, the lectin gave a single protein band with molecular masses of 19 and 38 kDa in the presence and absence of 2-mercaptoethanol, respectively. CJA-B contained mannose, N-acetylglucosamine, xylose, and fucose in the molar ratio of 3.0:1.6:1.2:1.1. The protein required calcium ions for hemagglutinating activity and showed specificities for alpha-galactosyl and alpha-glucosyl residues. Studies on hemagglutination inhibition by Synsorbs, which are synthetic oligosaccharides coupled chemically to crystalline silica, showed that the lectin mainly interacts with Gal alpha 1-3Gal.     

Purification and characterization of a mannose/N-acetyl-D-glucosamine-specific lectin from the seeds of Platymiscium floribundum Vogel

Platymiscium floribundum lectin (PFL), a mannose/N-acetyl-D-glucosamine-specific lectin, was isolated from P. floribundum seeds using Sepharose-mannose affinity media chromatography. PFL is a glycoprotein that is a potent agglutinin for rabbit erythrocytes. In addition, PFL is highly stable because it is able to maintain its hemagglutinating activity after exposure to temperatures of up to 60 °C for 1 h and exposure to a wide pH range. The PFL purification process was monitored using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the results showed that the purified lectin consists of a single band with a molecular mass of approximately 29 kDa in either the presence or the absence of a reducing agent. The analysis of purified PFL by electrospray ionization-mass spectrometry showed that most ions had a molecular weight of 27,053 ± 2 Da, and other less abundant ions had similar molecular weights. Gel filtration shows that the lectin exists as a dimer in solution with mass at approximately 65 kDa. Sixteen peptides were sequenced, and as a result, a total of 130 amino acids were identified and resulted in a coverage of approximately 65% of the PFL sequence. The partial sequence of PFL was aligned with sequences of other lectins from evolutionarily related species, and PFL showed considerable similarity to the other lectins.     

Glycoprotein characteristics of the sodium channel saxitoxin-binding component from mammalian sarcolemma

The saxitoxin-binding component of the excitable membrane sodium channel exhibits glycoprotein characteristics as evidenced by its specific interaction with various agarose-immobilized lectins. The detergent-solubilized saxitoxin-binding component interacts quantitatively with immobilized wheat germ agglutinin and concanavalin A and fractionally with immobilized Lens culinaris hemagglutinin and Ricinus communis agglutinin. These lectins preferentially bind $\text{N-}\text{acetylglucosamine}$ and sialic acid (wheat germ agglutinin), mannose (concanavalin A and Lens cunilaris and galactose (Ricinus communis). Removal of terminal sialic acid residues by neuraminidase markedly decreases binding to immobilized wheat germ agglutinin but uncovers sites capable of interacting with lectins specific for galactose and $\text{N-}\text{acetylgalactosamine}$. $\text{β-N-}\text{acetylglucosaminidase}$, an exoglycosidase has no effect on the binding of the channel protein to wheat germ agglutinin. Similarly, phospholipase C has no effect on binding of the solubilized toxin binding component to this lectin. Neither wheat germ agglutinin nor concanavalin A free in solution alters the number of toxin binding sites or their affinity for toxin. The sodium channel saxitoxin-binding component appears to be a glycoprotein containing terminal sialic acid residues and internal mannose, galactose, $\text{N-}\text{acetylglucosamine}$, and $\text{N-}\text{acetylgalactosamine}$ residues. The toxin binding site is spatially separated from the binding sites for the lectins studied. The effect of these sugar moieties must be considered when evaluating the biophysical parameters of the sodium channel.     

Effect of amino acid residue and oligosaccharide chain chemical modifications on spectral and hemagglutinating activity of Millettia dielsiana Harms. ex Diels. lectin

The effects of modifying the carbohydrate chain and amino acids on the conformation and activity of Millettia dielsiana Harms. ex Diels. lectin (MDL) were studied by hemagglutination, fluorescence and circular dichroism analysis. The modification of tryptophan residues led to a compete loss of hemagglutinating activity; however, the addition of mannose was able to prevent this loss of activity. The results indicate that two tryptophan residues are involved in the carbohydrate-binding site. Modifications of the carboxyl group residues produced an 80% loss of activity, but the presence of mannose protected against the modification. The results suggest that the carboxyl groups of aspartic and glutamic acids are involved in the carbohydrate-binding site of the lectin. However, oxidation of the carbohydrate chain and modification of the histidine and arginine residues did not affect the hemagglutinating activity of MDL. Fluorescence studies of MDL indicate that tryptophan residues are present in a relatively hydrophobic region, and the binding of mannose to MDL could quench tryptophan fluorescence without any change in λmax. The circular dichroism spectrum showed that all of these modifications affected the conformation of the MDL molecule to different extents, except the modification of arginine residues. Fluorescence quenching showed that acrylamide and iodoacetic acids are able to quench 77% and 98% of the fluorescence of tryptophan in MDL, respectively. However, KI produced a barely perceptible effect on the fluorescence of MDL, even when the concentration of I^- was 0.15M. This demonstrates that most of tryptophan residues are located in relatively hydrophobic or negatively charged areas near the surface of the MDL molecule.     

Specific changes in the oligosaccharide moieties of VSV grown in different lectin-resistnat CHO cells.

The carbohydrate moieties of the G glycoprotein of vesicular stomatitis virus (VSV) grown in three distinct lectin-resistant (LecR) Chinese hamster ovary (CHO) cell lines have been compared by fine structural analysis of radiolabeled glycopeptides. The mutant WgaRIII, selected for resistance to wheat germ agglutinin (WGA), produces VSV containing G glycoprotein specifically lacking in sialic acid. The mutant PhaRI, selected for resistance to phytohemagglutinin (PHA) and previously shown to lack a particular glycoprotein N-acetyl-glucosaminyl-transferase activity, produces VSV containing G glycoprotein specifically lacking terminal N-acetylglucosamine-galactose-sialic acid sequences and possessing an increased number of mannose residues in the "core" region of its carbohydrate moieties. The mutant PhaRIConARII, a "double" mutant selected from PhaRI cells for resistance to concanavalin A (ConA), produces VSV containing G glycoprotein with a further alteration in the mannose residues of the "core" oligosaccharide region. We discuss the relevance of these findings to the mechanisms of glycoprotein biosynthesis in mammalian cells and to the biochemical bases of lectin resistance in CHO cells.     

Deficient uridine diphosphate-N-acetylglucosamine:glycoprotein N-acetylglucosaminyltransferase activity in a clone of Chinese hamster ovary cells with altered surface glycoproteins.

We have reported the isolation of a clone (termed 15B) of Chinese hamster ovary (CHO) cells which are deficient in certain plant lectin-binding sites and have decreased amounts of sialic acid, galactose, and N-acetylglucosamine in its membranes (Gottlieb et al. (1974) Proc. Natl. Acad. Sci. U.S.A. 71, 1078-1082). This study demonstrates that extracts of 15B cells, in contrast to the parent cell line, do not transfer N-acetylglucosamine residues from UDP-GlcNAc to certain glycopeptide and glycoprotein acceptors containing terminal nonreducing alpha-linked mannose residues. The decreased enzyme activity could not be accounted for by the presence of inhibitors, altered pH, or Mn2+ requirements of the glycosyltransferase or increased N-acetylglucosaminidase activity in the extracts. The finding that the 15B cell extracts have significant but reduced N-acetylglucosaminyltransferase activity toward a degraded orosomucoid acceptor suggests that these cells have a selective loss of one of several specific N-acetylglucosaminyltransferases which are present in the parent CHO cells. The sialyl- and galactosyltransferase activities of 15B and parent CHO cells are comparable. Parent CHO and 15B cells were grown in radioactive glucosamine to label the membrane glycoproteins. Solubilization of these glycoproteins and passage over a Ricinus communis agglutinin I (RCA I) Sepharose affinity column revealed that no labeled 15B glycoprotein material bound, whereas 50 percent of the CHO membrane glycoproteins bound and could be eluted with the haptene lactose, demonstrating that 15B cells are virtually devoid of membrane oligosacharides capable of binding to the RCA I lectin. The 15B membrane glycoproteins exhibited a marked shift toward glycoprotein species of lower molecular weight when examined by gel electrophoresis in sodium dodecyl sulfate. It is proposed that this shift in the mobility of the 15B membrane glycoproteins results from a decreased glycosylation of a number of membrane glycoproteins relative to their counterparts in CHO cells. The deficient N-acetylglucosaminyltransferase activity in 15B cells can account for the decreased glycosylation of the 15B cell membrane glycoproteins.     

Characterization of surface glycoproteins on Schistosoma mansoni adult worms by lectin affinity chromatography

Adult Schistosoma mansoni were radiolabeled by direct radioiodination using the Bolton-Hunter reagent or by metabolic labeling using radioactive hexose precursors. Tegumental material was extracted by freeze-thaw or by incubation in the non-ionic detergent Nonidet P-40, then applied to chromatography columns containing the following immobilized lectins: Con A, lentil lectin, wheat germ agglutinin, soybean agglutinin and the agglutinins from Ricinus communis and Helix pomatia. SDS-PAGE analysis of the sugar eluates from these columns revealed the presence of 15 glycoproteins with apparent molecular weights greater than or equal to 300,000, 215,000, 168,000, 152,000, 134,000, 122,000, 108,000, 83,000, 58,000, 53,000, 46,000, 41,000, 34,000, 30,000 and 23,500. Many of the glycoproteins reacted with more than one lectin. Information about carbohydrate content and lectin binding provides a preliminary characterization of the tegumental glycoprotein antigens of adult worms.     

Lectin activity in pollen from plants representative of thirty orders of spermatophyta

Summary Pollen extracts from a variety of species representative of thirty orders of spermatophyta, including gymnosperms, dicotyledons and monocotyledons, were examined for the presence of lectin activity by means of a hemagglutination assay. Hemagglutinating activity (HA) was detected in the pollen extracts of all the species examined, indicating that lectins are generally present in the pollen of spermatophyta. The response of this pollen hemagglutinating activity to the sugars and glycoproteins tested as potential inhibitors was identical in all species examined. Moreover, the hemagglutinating activity of pollen extracts from eight species which had been selected as representative of the gymnosperms and both subclasses of angiosperms exhibited similar properties (e.g. distribution by differential centrifugation, stability to heat, response to bivalent ions). The bulk of the hemagglutinating activity was always recovered in the pellet after centrifugation at 1000 g for 5 min. Although sequential treatments with 1% Triton X-100 and 1 M KCl were ineffective, subsequent incubation of the pellet with saline phosphate buffer released hemagglutinating activity. The solubilized hemagglutinating activity was destroyed by protease treatment, indicating that the substance(s) responsible for the activity is (are) protein in nature and, consequently, might be considered to be a lectin. The sugar specifity of the pollen lectin activity from wheat, potato and bean was compared with that of wheat germ agglutinin (WGA), potato agglutinin and bean agglutinin — the lectins present in sporophytic tissues of these plants. For all three plants, the response of the pollen lectin activity to sugars and glycoproteins was different from that shown by the lectin from sporophytic tissues.Abbreviations HA Hemagglutinating activity - PBS 150 mM Na-phosphate buffer (pH 7.2) containing 0.9% NaCl - PHA Phaseolus vulgaris agglutinin - STA Solanum tuberosum agglutinin - WGA wheat germ agglutinin     

Purification and Characterization of the Acidic Lectin from Winged Bean Seeds

Winged bean acidic lectin was purified by DEAE-Sephadex A-50 and affinity chromatography on N-acetylgalactosamine-agarose gel. The purified lectin was a glycoprotein homogeneous on polyacrylamide gel electrophoresis, isoelectric focusing, and gel filtration. The molecular weight of the lectin was 52,000 by gel filtration, and SDS-polyacrylamide gel electrophoresis gave a single component of molecular weight of 27,000. Its isoelectric point was 5.5. The acidic lectin was rich in acidic amino acids, and contained 2mol of methionine but no cystine. It also agglutinated both trypsinized and untreated human erythrocytes (types A, B, AB and O), but not rabbit erythrocytes. The hemagglutination was inhibited by d-galactose and related sugars. Modification of the acidic lectin with N-bromosuccinimide caused a concomitant loss of the hemagglutinating activity with oxidation of tryptophan residue. The acidic lectin was immunologically different from the purified winged bean basic lectin by double immunodiffusion using antiserum raised against the basic lectin.     

Purification and characterization of a galactose-specific lectin from corn (Zea mays) coleoptyle

We purified and characterized a lectin from the corn coleoptyle (Zea mays). The lectin (CCL) was purified by affinity chromatography on a Lactosyl–Sepharose 4B column. It is a glycoprotein of 88.7 kDa, composed mainly by glutamic, aspartic, glycine, and Ser residues; in a minor proportion, it contained methionine and cysteine residues. Carbohydrates that constituted 12% of the total weight comprised galactose, mannose, and N-acetyl-D-glucosamine. The lectin contained the blocked amino-terminus. Analysis of the lectin, determined from peptides obtained after trypsin digestion by MALDI-TOF (matrix-assisted laser desorption ionization-time of flight), indicated that CCL has 18% homology with a putative calcium-dependent Ser/Thr protein kinase, from Arabidopsis thaliana, and 39% homology with a NADPH-dependent reductase from Z. mays. The lectin showed hemagglutinating activity toward several erythrocytes, including human A, B, and O. Hapten inhibition assays indicated that the lectin interacts specifically with the OH on C4 from galactose residues. OH- on C1 plays a relevant role in the interaction with CCL, since β-galactose residues are better recognized than those from the anomeric α-galactose. Lack of lectin activity was observed in corn extracts; the highest specific activity was obtained from coleoptyle obtained at the 7th day after seeding.     

Purification and characterization of a lectin from rice bran

A rice bran lectin was purified to homogeneity by precipitation with ammonium sulfate and chromatography on ovomucoid-Sepharose and CM-cellulose. The molecular weight of the dimer lectin was estimated to be around 37,000 by ultracentrifugation studies. The sedimentation coefficient was 3.8S. On Sepharose 6B gel filtration in the presence of 6 M guanidine-HCl, the lectin showed a molecular weight of 19,000. On reduction and carboxymethylation, the lectin further dissociated into two nonidentical subunits, with molecular weights of about 11,000 and 8,000. These subunits did not show hemagglutinating activity. Equilibrium dialysis experiments using N-acetyl-[1-14C]glucosamine indicated that about 1.8 mol of the sugar was bound to 19,000 g of the lectin. The lectin was mitogenic against mouse splenic lymphocytes and human peripheral lymphocytes. The lectin enhanced the rate of glucose oxidation and inhibited epinephrine-stimulated lipolysis in mouse adipocytes. Some characteristics of the lectin are compared with those of wheat germ agglutinin.     

On the stringent requirement of mannosyl substitution in mannooligosaccharides for the recognition by garlic (Allium sativum) lectin. A Surface Plasmon Resonance Study

The kinetics of the binding of mannooligosaccharides to the heterodimeric lectin from garlic bulbs was studied using surface plasmon resonance. The interaction of the bound lectin immobilized on the sensor chip with a selected group of high mannose oligosaccharides was monitored in real time with the change in response units. This investigation corroborates our earlier study about the special preference of garlic lectin for terminal alpha-1,2-linked mannose residues. An increase in binding propensity can be directly correlated to the addition of alpha-1,2-linked mannose to the mannooligosaccharide at its nonreducing end. Mannononase glycopeptide (Man9GlcNAc2Asn), the highest oligomer studied, exhibited the greatest binding affinity (Ka = 1.2 x 10(6) m(-1) at 25 degrees C). An analysis of these data reveals that the alpha-1,2-linked terminal mannose on the alpha-1,6 arm is the critical determinant in the recognition of mannooligosaccharides by the lectin. The association (k1) and dissociation rate constants (k(-1)) for the binding of Man9GlcNAc2Asn to Allium sativum agglutinin I are 6.1 x 10(4) m(-1) s(-1) and 4.9 x 10(-2) s(-1), respectively, at 25 degrees C. Whereas k1 increases progressively from Man3 to Man7 derivatives, and more dramatically so for Man8 and Man9 derivatives, k(-1) decreases relatively much less gradually from Man3 to Man9 structures. An unprecedented increase in the association rate constant for interaction with Allium sativum agglutinin I with the structure of the oligosaccharide ligand constitutes a significant finding in protein-sugar recognition.     

The glycosylation status of murin postnatal thymus: a study by histochemistry and lectin blotting

During the intrathymic development, the fate of the thymocytes depends largely on variable expression of CD4/CD8 markers and T cell receptor protein expressions. In addition, changes of cell surface glycosylation status also affect the thymocyte maturation. In this study the glycosylation alterations in thymic tissues from 1, 9, 13 and 16 days old mice were evaluated by histochemical and lectin blotting techniques. With alcian blue (AB) at pH 5.7/periodic acid-Schiff (PAS) stainings, it was shown that thymic microenvironments contained carboxlylated and sulfated glycosaminoglycans (GAGs). Strong positivity to AB at pH 2.5, which specific for sialomucins, was seen in some medullary thymocytes. Similarly, it was shown that with Maackia amurensis agglutinin (MAL) medullary thymocytes, but not cortical ones, contained alpha(2 --> 3) linked sialic acid structures. On the other hand, while reaction with peanut agglutinin (PNA), which specific for core disaccharide galactose beta(1 --> 3) N-acetylgalactosamine, was only seen in cortical thymocytes, reaction with Galanthus nivalis agglutinin (GNA), which specific for terminal mannose residues, was seen in both cortex and medulla. However, Datura stramonium agglutinin (DSA), which recognizes galactose beta(1 --> 4) N-acetylglucosamine, was not only cell-specific, but it was bound some thymic vessels. With lectin blotting studies, five glycoprotein bands of molecular weights ~39, ~54, 100, ~110 and ~212 were found which reacted with MAL, PNA and DSA as well as GNA. These results suggest that glycosylation patterns of cell surface glycoconjugates are modified during thymocyte selection processes of postnatal days.     

Localization of prostatic glycoconjugates by the lectin-gold method.

The glycoconjugates of the lateral prostate were examined ultrastructurally by lectin-gold histochemistry in combination with a low-temperature embedding technique using Lowicryl K4M. The binding patterns of concanavalin A, wheat germ agglutinin, Griffonia simplicifolia, soybean agglutinin, peanut agglutinin, Ricinus communis agglutinin isolectin I, Griffonia simplicifolia isolectin B4, Ulex europaeus isolectin I and Phaseolus vulgaris agglutinin P have been documented in the subcellular compartments of the lateral prostate. The results show that the granular endoplasmic reticulum (GER) is rich in glycoproteins with mannosyl residues while the Golgi cisternae, secretory granules and microvilli are less so. The mannose (Man) and N-acetylglucosamine (GlcNAc) residues present in the GER of the epithelial cells may be associated with the initial assembly of the N-linked oligosaccharides of glycoproteins. The secretory granules exhibited different reactivities to lectins. Most of the lectin-binding sites confined to the limiting membranes may play a role in the transport of plasmalemma glycoconjugates to the apical plasma membrane. The epithelial Golgi stack is rich in GlcNAc, galactose (Gal), N-acetylgalactosamine (GalNAc) and sialic acid residues, and a compartmental organization of the Golgi stack is apparent which might be associated with the sequential addition of sugar residues to the oligosaccharides. The plasma membrane contains abundant Man, GlcNAc, Gal, GalNAc and complex carbohydrates, especially in the microvilli, and a differential lectin labelling was noted between the apical and basolateral plasma membrane. The present study showed that fucose-containing glycoconjugates were detected in the apical plasma membrane of the lateral prostate. The stromal extracellular matrices as well as the epithelial basement membranes demonstrated weak lectin reaction. Man, GlcNAc, Gal residues and complex sugars were also noted in the stromal tissues of the lateral prostate including the extracellular matrix, capillaries and smooth muscle.