Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rhodopsin's oligosaccharide chains contain predominantly two types of sugar residues: mannose and N-acetylglucosamine. In the present work, bovine and rat rhodopsin were analysed biochemically for the presence of a third sugar, galactose. Treatment of bovine rod outer segments (ROS) with galactose oxidase followed by reduction with tritium-labeled sodium borohydride revealed the presence of existing molecules of galactose on rhodopsin. Rats injected intravitreally with [3H]galactose and [14C]leucine and maintained in darkness were killed 1 hr, 6 hr, 1, 3 or 5 days following the injection. Retinas were collected for subcellular fractionation and rhodopsin from each of the fractions was purified by ConA sepharose chromatography and SDS-PAGE. During the first 6 hr, galactose selectively labeled rhodopsin in the Golgi-enriched fraction resulting in increased [3H]/[14C] ratios in both Golgi and ROS. The data suggested that trimming was occurring at the transition from Golgi to ROS. Furthermore, a decrease in isotope ratio in the ROS between 6 hr and 1 day suggested further trimming of rhodopsin after membrane assembly in the ROS. Additional in vivo experiments demonstrated existing molecules of galactose on rhodopsin's oligosaccharide chain using lectin affinity chromatography. Rats injected intravitreally with [35S]methionine were dark-adapted for 2 hr. Following subcellular fractionation of retinas, ConA purified rhodopsin from ROS was applied to one of two additional lectin columns: Ricinus communis agglutinin (RCA) or Griffonia simplicifolia I (GSA). Eight to nine percent of the labeled rhodopsin was bound to and eluted from RCA, whereas none bound to GSA, indicating the presence of a beta-galactoside. The RCA agarose eluted protein co-electrophoresed with a rhodopsin standard and was light sensitive. Galactose was shown to be the terminal sugar on this subset of rhodopsin and was not capped by neuraminic acid. Binding of rhodopsin's oligosaccharide to RCA was abolished by pre-treatment with beta-galactosidase. Decreased binding of rhodopsin to RCA was observed following intravitreal injection of castanospermine but not swainsonine. Of those two inhibitors of glycoprotein trimming, only castanospermine would be expected to prevent the addition of galactose to the oligosaccharide. The association of galactose with rat rhodopsin appeared to be a transient one. At 2 hr, 8-9% of rhodopsin contained galactose, at 6 hr only 2.2% had galactose and by 24 hr less than 1% did. The galactose was trimmed from rhodopsin's oligosaccharide presumably after its role was complete. Separation of rhodopsin of the plasma membranes from rhodopsin of discs indicated that 75% of the galactose-containing rhodopsin was in the plasma membrane and only 25% was in the discs. These findings suggested a possible role for galactose in new disc formation with subsequent removal after the discs are sealed.
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PMID:Transient hyperglycosylation of rhodopsin with galactose. 193 88

The structure of the N-linked oligosaccharide of the 85-kDa surface glycoprotein (Tc-85) from the infective trypomastigote form of Trypanosoma cruzi was investigated. Tc-85 metabolically labeled with [14C]glucose was purified by affinity chromatography on wheat germ agglutinin-Sepharose. Binding to the lectin was lost on treatment of Tc-85 with neuraminidase. The N-linked asialo-oligosaccharide was released by endo-beta-N-acetylglucosaminidase F digestion of asialo-Tc-85 and was further analyzed using specific exoglycosidases. [14C]fucose was detected after alpha-L-fucosidase treatment or mild acid hydrolysis. The afucosyl oligosaccharide was 3H-labeled by the galactose oxidase-NaB3H4 method. [3H]Galactose was released by alpha-galactosidase, and only then was beta-galactosidase effective in removing another galactose. The gal(alpha 1-3)gal unit was demonstrated by periodate oxidation studies on the [3H]galactose-labeled asialo-glycoprotein. The presence of gal(alpha 1-3)gal in Tc-85 could be related to the recent finding of elevated antibody levels against this epitope in patients with Chagas' disease.
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PMID:The N-linked carbohydrate chain of the 85-kilodalton glycoprotein from Trypanosoma cruzi trypomastigotes contains sialyl, fucosyl and galactosyl (alpha 1-3)galactose units. 210 74

Asparagine-linked sugar chains of sphingolipid activator protein 1 (SAP-1) purified from normal human liver and GM1 gangliosidosis (type 1) liver were comparatively investigated. Oligosaccharides released from the two SAP-1 samples by hydrazinolysis were fractionated by paper electrophoresis and by Aleuria aurantia lectin-Sepharose and Bio-Gel P-4 (under 400 mesh) column chromatography. Structures of oligosaccharides in each fraction were estimated from data on their effective molecular sizes, behavior on immobilized lectin columns with different carbohydrate-binding specificities, results of sequential digestion by exoglycosidases with different aglycon specificities, and methylation analysis. Sugar chains of SAP-1 purified from normal human liver and from GM1 gangliosidosis (type 1) liver were different from each other, although both of them were derived from complex-type sugar chains. The sugar chains of the former were the following eight degradation products from complex-type sugar chains by exoglycosidases in lysosomes: Man alpha 1----6(Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4GlcNAcOT, Man alpha 1----6(Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4(Fuc alpha 1----6)GlcNAcOT, Man alpha 1----6Man beta 1----4GlcNAc beta 1----4GlcNAcOT, Man alpha 1----6Man beta 1----4GlcNAc beta 1----4(Fuc alpha 1----6)GlcNAcOT, Man beta 1----4GlcNAc beta 1----4GlcNAcOT, Man beta 1----4GlcNAc beta 1----4(Fuc alpha 1----6)GlcNAcOT, GlcNAc beta 1----4GlcNAcOT, and GlcNAcOT. In contrast to these, the sugar chains of the latter were sialylated and nonsialylated mono- to tetraantennary complex-type sugar chains that were not fully degraded due to a metabolic defect in acid beta-galactosidase activity.
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PMID:Characteristics of asparagine-linked sugar chains of sphingolipid activator protein 1 purified from normal human liver and GM1 gangliosidosis (type 1) liver. 211 Aug 22

Studies on the differentiation and activation of human monocytes in tissue cultures have usually been limited by the deterioration of human monocytes and macrophages in long-term cultures. In this study, we attempted to establish long-term human monocyte/macrophage cultures using the phorbol ester 12-0 tetradecanoyl-phorbol-13-acetate (TPA), and we studied the morphology, function, and biochemical properties of such treated human blood monocytes. Enriched suspensions of monocytes were obtained using Ficoll-Hypaque gradient and cultured in the absence or presence of various concentrations of TPA. Samples were removed at different times and processed for scanning electron microscopy. Parallel samples were examined for numbers of adherent cells, phagocytosis, oxidative burst, beta-galactosidase assays, and lectin-mediated erythrolysis. TPA-treated monocytes survived in larger numbers in culture for up to 7 weeks and were more pleomorphic and exhibited higher beta-galactosidase activities after 14 days in culture than untreated monocytes. TPA-treated cells and untreated cells in long-term cultures showed a decrease in their oxidative burst activity while their phagocytic activity was not affected, and the TPA treatment augmented the lysis of wheat germ agglutinin-opsonized erythrocytes by the cultured monocytes. TPA treatment of adherent human monocytes resulted in cell cultures with increased numbers of viable and functionally adherent cells for extended periods of time and does not seem to interfere with the differentiation and maturation of the cells in culture.
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PMID:Interaction between human peripheral blood monocytes and tumor promoters: effect on growth differentiation and function in vitro. 211 62

Monoclonal antibodies 18H4 and 19F12 against alpha-foetoprotein (AFP) were examined by enzyme immunoassay for binding to two forms of AFP that were separated on the basis of the reactivity with lentil lectin (LCA). LCA-binding and LCA non-binding AFP, coated on a solid phase, reacted with 18H4 but reactivity with the LCA-binding species was inhibited by 60% following pretreatment of the AFP with LCA. The lectin was a very poor inhibitor of binding of 18H4 to the AFP which did not interact with LCA. In an alternative binding assay, a polyclonal anti-AFP coated solid phase was reacted with beta-galactosidase-labelled 18H4. Pre-treatment with LCA of the LCA-reactive AFP gave 56% inhibition of binding of conjugated 18H4 while little inhibition was achieved with the LCA-nonreactive AFP component. These findings show that the epitope recognised by 18H4 is distinct from the glycan sequence that is reactive with LCA. However, the LCA-binding oligosaccharides occur in close proximity to the 18H4 epitope in the native AFP.
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PMID:Close topographical relationship in alpha foetoprotein (AFP) between a lens culinaris binding glycan and the epitope recognized by AFP-reactive monoclonal antibody, 18H4. 243 21

We examined the effects of alpha-L-fucosidase digestion on lectin staining in formalin-fixed, paraffin-embedded human pancreatic tissue from individuals of different blood groups. Digestion with the enzyme resulted in apparent diminished intensity of Ulex europaeus agglutinin-I (UEA-I) staining in the acinar cells. In addition to the decreased intensity of UEA-I staining, reactivity with soybean agglutinin (SBA) was increased in the enzyme-susceptible, UEA-I-reactive cells. The intensity of Griffonia simplicifolia agglutinin-II (GSA-II) staining performed after beta-galactosidase digestion in UEA-I-reactive acinar cells was markedly increased by prior treatment with fucosidase. GSA-II staining following sequential digestion with fucosidase and galactosidase was completely abolished by subsequent digestion with beta-N-acetylhexosaminidase. These results therefore substantiate the previous assumption that SBA-reactive D-galactose-(beta 1-3,4)-N-acetyl-D-glucosamine and GSA-II reactive beta-N-acetyl-D-glucosamine imparted following galactosidase digestion represent precursors of H antigen. The present study further demonstrated that intense peanut agglutinin (PNA) staining was imparted after digestion with fucosidase in UEA-I-reactive sites in secretors. In contrast, nonsecretors showed vivid PNA staining that was usually detected throughout the pancreas without prior enzyme digestion. Here, fucosidase digestion had if any little effect on PNA staining. These results suggest that in secretors a terminal trisaccharide, fucosylated D-galactose-(beta 1-3)-N-acetyl-D-galactosamine exhibiting positive PNA reaction after fucosidase digestion, exists in UEA-I-reactive acinar cells. It is assumed that the secretor gene could control the step of final fucosylation of D-galactose-(beta 1-3)-N-acetyl-D-galactosamine in human pancreas.
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PMID:Effects of alpha-L-fucosidase digestion on lectin staining in human pancreas. 245 90

Effects of alpha-galactosidase (from green coffee beans) digestion on lectin staining were examined in formalin-fixed, paraffin-embedded human pancreatic tissues from individuals of blood-group B and AB. Digestion with the enzyme resulted in almost complete loss of Griffonia simplicifolia agglutinin I-B4 (GSAI-B4) staining in the acinar cells with concomitant appearance of Ulex europaeus agglutinin-I(UEA-I) staining in the corresponding cells. In addition, reactivity with soybean agglutinin(SBA) was also imparted by the enzyme digestion in GSAI-B4 positive acinar cells. beta-Galactosidase digestion following alpha-galactosidase digestion neither reduced the reactivity with SBA nor induced the reactivity with Griffonia simplicifolia agglutinin-II(GSA-II) in GSAI-B4 positive cells, while in UEA-I positive cells, both reduction of SBA reactivity and appearance of GSA-II reactivity occurred after simple beta-galactosidase digestion as well as sequential digestion with alpha- and beta-galactosidase. However, when alpha-L-fucosidase digestion procedure was inserted between alpha- and beta-galactosidase digestion, UEA-I staining imparted by alpha-galactosidase digestion was markedly decreased in intensity and GSA-II reactivity was appeared in GSAI-B4 positive acinar cells. Furthermore, after sequential digestion with alpha-galactosidase and fucosidase, reactivity with peanut agglutinin(PNA) was revealed in GSAI-B4 positive acinar cells as well as UEA-I positive cells in secretors. In non-secretors, strong PNA staining was usually observed in the acinar cells throughout the glands without enzyme digestion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of alpha-galactosidase digestion on lectin staining in human pancreas. 245 77

The subcellular distribution of sialyltransferase and its product of action, sialic acid, was investigated in the undifferentiated cells of the rat intestinal crypts and compared with the pattern observed in the differentiated cells present in the surface epithelium. Sialyltransferase was immunocytochemically detected with an antibody, affinity-purified on a beta-galactosidase/sialyltransferase fusion protein, which recognizes only protein epitopes of the enzyme. A similar pattern and intensity of immunolabeling were observed in the Golgi apparatus, apical and basolateral plasma membranes of both undifferentiated and differentiated absorptive cells. However, in the goblet cells, the mucus was only weakly labeled in cells present in the basal portion of the crypts but increased in intensity through the zone of migration to the surface epithelium. Sialic acid as detected with the Limax flavus lectin was observed in the Golgi apparatus and post-Golgi apparatus structures of both absorptive and goblet cells regardless of their position along the crypt-to-surface epithelium axis. However, a striking difference in the plasma membrane distribution of sialic acid existed between undifferentiated cells of the lower half of the crypts and those of the upper half and the surface epithelium: in the former, label was present in both the apical and basolateral domain, whereas in the latter it became restricted to the apical domain. These results suggest that the presence of sialyltransferase immunoreactivity in the goblet cell mucus and the polarization of sialic acid to the apical plasma membrane of both goblet and absorptive cells may be markers for the differentiated state.
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PMID:Alteration in sialyltransferase and sialic acid expression accompanies cell differentiation in rat intestine. 245 28

Using lectin staining methods in combination with exo- and endo-glycosidase digestion procedures, we analyzed the chemical structure of different types of blood group-related substances in serous cells of formalin-fixed, paraffin-embedded human submandibular glands. Serous cells produced only H antigen; A and B antigens were not present, and the expression of H antigen is dependent on the secretor status of the tissue donor. Although reactivity with Ulex europaeus agglutinin I (UEA-I) was not markedly reduced by alpha-L-fucosidase digestion, an affinity for peanut agglutinin (PNA) was seen after fucosidase digestion in the cells from secretors. In those from nonsecretors, no PNA reactivity appeared after enzyme digestion. On the other hand, sialidase digestion elicited PNA reactivity in serous cells irrespective of the donor's secretor status. PNA reactivity observed after fucosidase or sialidase digestion was susceptible to endo-alpha-N-acetylgalactosaminidase (endo-GalNAc-dase) digestion. SBA reactivity in UEA-I-negative cells from secretors, or in cells from fetuses and newborn infants, was markedly reduced by beta-galactosidase digestion. After galactosidase digestion, reactivity with Griffonia simplicifolia agglutinin II (GSA-II) appeared in the corresponding cells. This GSA-II reactivity was almost completely eliminated by subsequent beta-N-acetylhexosaminidase digestion. Whereas PNA reactivity in these cells was not reduced by beta-galactosidase treatment, it was significantly diminished by endo-GalNAc-dase digestion. These results suggest that at least two kinds of precursor disaccharides are produced in submandibular serous cells, i.e., SBA-reactive D-galactose-(beta 1-3,4)-N-acetyl-D-glucosamine and PNA-reactive D-galactose-(beta 1-3)-N-acetyl-D-galactosamine alpha 1-serine or threonine (O-glycosidically linked Type 3 chain or T antigen). Final fucosylation and synthesis of these two types of precursor chain appear to be under the control of the secretor gene.
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PMID:Histochemical analysis of the chemical structure of blood group-related carbohydrate chains in serous cells of human submandibular glands using lectin staining and glycosidase digestion. 249 20

Fluorescein isothiocyanate (FITC)-labelled asialotransferrin and pyridyl aminated oligosaccharides were prepared from asialotransferrin and human milk using affinity chromatography and high performance liquid chromatography (HPLC), respectively. These substances were incubated with galactosidase or sialyltransferase and then examined by lectin affinity HPLC. The elution patterns changed according to the period of incubation and amount of enzyme. This analytical method using lectin affinity HPLC with fluorescence labelled glycoprotein or oligosaccharides as the substrates has great value for detecting these enzyme under the same chromatographic conditions. In addition, differences were noted in the activity of beta-galactosidase toward oligosaccharides having the Gal beta(1----3)GlcNAc or Gal beta(1----4)GlcNAc structure at reducing termini.
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PMID:Rapid assay of beta-galactosidase and sialyltransferase by lectin affinity high performance liquid chromatography with fluorescence detection. 250 11


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