Browsing by Author "APPUKUTTAN, PS"

Now showing 1 - 14 of 14
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    ALPHA-GALACTOSIDE-BINDING ISOLECTINS FROM WILD JACK FRUIT SEED (ARTOCARPUS-HIRSUTA) - PURIFICATION AND PROPERTIES
    (INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS, 1989) ANTONY, L; BASU, D; APPUKUTTAN, PS
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    ANOMER SPECIFICITY OF THE 14-KDA GALACTOSE-BINDING LECTIN - A REAPPRAISAL
    (JOURNAL OF BIOSCIENCES, 1995) APPUKUTTAN, PS; GEETHA, M; ANNAMMA, KI
    A beta-anomer preference among galactosides has been attributed to the S-type 14 kDa galactose binding lectin. Here the anomeric preference of this lectin from bovine brain (BBL) is reexamined using inhibition of lectin-mediated haemagglutination, binding of the lectin to dot-blotted glycoproteins and affinity electrophoresis of the lectin through polysaccharide-containing gels. 1-O-methyl alpha-D-galactoside was 8 times better inhibitor of BBL than the corresponding beta-anomer. The terminal galactose in bovine thyroglobulin (exclusively alpha-linked) were also nearly 8 times more inhibitory than those in asialofetuin (exclusively beta-linked). The terminal alpha-galactose-containing endogenous glycoproteins of bovine brain were nearly 4 times better inhibitors of BBL than laminin. Removal of terminal alpha-galactose units by alpha-galactosidase fully abolished the BBL binding of thyroglobulin and endogenous glycoproteins. BBL was also sugar-specifically retarded by polyacrylamide gel containing guar galactomannan which bears only alpha-linked galactose. Data indicated that alpha-galactosides were sometimes better than their beta-anomers in binding to BBL. The significance of this observation to the physiological role of galactose-binding lectins is discussed.
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    BRAIN 14 KDA LECTIN PREFERS ALPHA-ANOMER OF GALACTOSE
    (JOURNAL OF NEUROCHEMISTRY, 1994) APPUKUTTAN, PS; GEETHA, M; ANNAMMA, KI
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    EPITOPES RECOGNIZED BY SERUM ANTI-ALPHA-GALACTOSIDE ANTIBODY ARE PRESENT ON BRAIN GLYCOPROTEINS IN MAN
    (JOURNAL OF BIOSCIENCES, 1993) JAISON, PL; KANNAN, VM; GEETHA, M; APPUKUTTAN, PS
    Naturally occurring serum IgG against terminal alpha-galactoside epitopes (anti-Gal), present exclusively in man, apes and old world monkeys, was used as probe for these epitopes in human brain. Human brain grey matter soluble glycoproteins enriched in alpha-galactosyl groups by affinity chromatography on jacalin-sepharose, specifically binds to human anti-Gal in immuno dot blots. Anti-Gal recognized exclusively the terminal alpha-galactoside epitope in human brain glycoproteins since binding was abolished by the presence of 1-0-methyl alpha-D-galactopyranoside as well as by pretreatment of glycoproteins with coffee bean alpha-galactosidase. Anti-Gal-peroxidase staining of jacalin-binding human brain glycoproteins in western immuno blots revealed mainly five anti-Gal-binding polypeptides with M(r) (in kDa) of 94, 108, 180, 210 and 230 respectively. Since the presence of anti-Gal in higher animals accompanies suppression of the corresponding epitope in most tissues, apparently to maintain immunological balance, possible implications of the above observation for autoimmunity, tumor metastasis and infection are discussed.
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    GAL-ALPHA-1-]3GAL-SPECIFIC ANTIBODIES
    (CURRENT SCIENCE, 1990) APPUKUTTAN, PS
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    HUMAN BRAIN CREATINE-KINASE BINDING TO IMMOBILIZED CIBACRON BLUE F3GA - CHARACTERIZATION AND USE IN PURIFICATION OF THE ENZYME
    (INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS, 1992)
    Creatine kinase (ATP: creatine N-phosphotransferase, EC 2.7.3.2) from adult human brain grey matter was purified by cibacron blue F3GA-Sepharose affinity chromatography. By gel electrophoresis of the purified enzyme under non-denaturing conditions a single protein band was observed. The dye-bound enzyme was eluted using its substrate, ATP. Reversibility of the binding of purified creatine kinase to blue Sepharose by ATP in a concentration-dependent manner indicated that the cibacron blue molecule which structurally mimics nucleotides occupied the substrate binding site of the enzyme. Also the marked dependence of enzyme binding to blue Sepharose on Mg2+ concentration suggested that Mg2+ ion is capable of combining with the dye moiety to form a site-specific binding complex that is similar to the physiological substrate of creatine kinase, namely Mg2+-ATP or Mg2+-ADP.
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    IDENTIFICATION OF ENDOGENOUS SOLUBLE GLYCOPROTEIN RECEPTORS OF BOVINE BRAIN GRAY-MATTER 14 KDA BETA-GALACTOSIDE-BINDING LECTIN
    (INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS, 1994)
    The 14 kDa beta-galactoside-binding lectin from bovine brain grey matter (BBL) covalently attached to caproic acid-Sepharose by the N-hydroxy succinimide procedure was used to isolate endogenous glycoprotein receptors of this lectin. BBL-Sepharose could sugar-specifically retain several endogenous soluble glycoproteins with subunit molecular mass(in kDA) 44, 51, 60, 123 and 186. BBL, conjugated with horse radish peroxidase, could sugar-specifically recognize several glycoprotein subunits with molecular mass (in kDA) 58, 87, 117 and 186 on Western blots. The only protein from an extract of bovine brain grey matter, that retained on Sepharose-immobilized endogenous N-linked glycoproteins and subsequently eluted with beta-galactosides was BBL as confirmed by electrophoresis and agglutination inhibition measurement. N-linked glycoproteins from-bovine heart and even from human placenta were also efficient receptors of BBL. These results suggest that 14 kDa beta-galactoside-binding lectin is the major protein, if not the only one, that sugar-specifically interacts with endogenous soluble glycoproteins in bovine brain grey matter.
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    INTERACTIONS OF THORIUM AND CERIUM WITH ADENINE-NUCLEOTIDES
    (BIOCHEMISTRY INTERNATIONAL, 1989) SHIVAKUMAR, K; APPUKUTTAN, PS; KARTHA, CC
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    MAJOR BOVINE BRAIN-STEM GLYCOPROTEINS SUGAR-SPECIFICALLY RECOGNIZED BY ENDOGENOUS 14 KDA GALACTOSE-BINDING LECTIN
    (INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS, 1994)
    In order to identify the complementary glycoproteins (receptors) that are recognized in bovine brain stem by endogenous 14 kDa galactose-binding lectin (BBL), probable glycoproteins were first selected by affinity chromatography of soluble tissue glycoproteins on Rinicus communis agglutinin (RCB) - Sepharose since this lectin had similar sugar specificity to the endogenous,lectin. From Western blot of RCA-binding glycoproteins, the lectin, as its peroxidase conjugate sugar-specifically recognized chiefly an 84 kDa glycoprotein subunit and a few minor subunits. On alkaline pH PAGE of the RCA-binding brain stem glycoproteins, a prominent fast moving protein was separated which, on electroelution and dot blotting, was also recognized by BBL sugar-specifically. This glycoprotein was composed of 55 kDa and 58 kDa subunits as seen by SDS-PAGE and was also immunologically distinct from the 84 kDa subunit. Qualitative test on dot blots of the electroeluted glycoproteins using peroxidase conjugates of plant lectins of varying specificities as well as the human serum anti-alpha-galactoside antibody indicated differences in carbohydrate composition between the 84 kDa subunit and the alkaline; PAGE fast moving glycoprotein. Membrane-bound brain stem glycoproteins were not recognized by BBL.
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    OLIGOSACCHARIDE STRUCTURE DETERMINATION OF GLYCOCONJUGATES USING LECTINS
    (JOURNAL OF BIOSCIENCES, 1987) BASU, D; NAIR, JV; APPUKUTTAN, PS
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    PHYSICOCHEMICAL PROPERTIES AND BINDING-SITE AMINO-ACID-RESIDUES OF GALACTOSIDE-BINDING PROTEIN OF HUMAN-PLACENTA
    (JOURNAL OF BIOSCIENCES, 1987) NAMBIAR, MP; BASU, D; APPUKUTTAN, PS
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    RAPID ISOLATION OF HUMAN PLASMA ANTI-ALPHA-GALACTOSIDE ANTIBODY USING SUGAR-SPECIFIC BINDING TO GUAR GALACTOMANNAN OR AGAROSE
    (INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS, 1992)
    A method of purifying the naturally occurring antibody to alpha-galactoside moiety (anti-alpha-Gal) in human plasma by a single-step affinity chromatography on cross-linked guar galactomannan (CLGG) or agarose (Sepharose 4B) is described. IgG nature of the two preparations, as revealed by agar gel diffusion, as well as their preference for alpha-anomer of galactose, as revealed in inhibition of their agglutination of trypsinized rabbit erythrocytes by sugars, identified them with anti-alpha-Gal. The antibody binding capacity of Sepharose 4B was only a third of that of CLGG. Both gels showed similar dependence on ionic strength for binding. The pH optimum for binding of anti-alpha-Gal to CLGG was 8.0. Significantly anti-alpha-Gal binding to Sepharose was unaffected by CNBr activation and ligand coupling to the gel, thus warning that contaminating plasma could introduce artifacts in agarose-based chromatography of human tissue biomolecules.
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    SUGAR-SPECIFIC INTERACTION OF BOVINE BRAIN BETA-GALACTOSIDE-BINDING LECTIN WITH ENDOGENOUS GANGLIOSIDES
    (INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS, 1993)
    Sugar-specific binding of the 14 kDa beta-galactoside-binding lectin from bovine brain grey matter to mixed endogenous gangliosides was demonstrated by affinity electrophoresis and heamagglutination inhibition. Gangliosides prepared by Folch extraction, base treatment and silica gel chromatography, when incorporated in native or desialylated form in polyacrylamide gel above their critical micellar concentration, arrested the mobility of the lectin during electrophoresis at pH 8.2. This effect was sugar-specific since it was reversed if lactose, but not sucrose, was present in the gel. Also, retention of the brain lectin by ganglioside and its reversal by lactose were concentration-dependent. In presence of bovine serum albumin, at pH 7.4 native and desialylated gangliosides equally inhibited agglutination of trypsinized rabbit red cells by bovine brain lectin, but not that by the alpha-galactoside-specific antibody from human serum. Results suggested the possibility of endogenous gangliosides acting as cell surface receptors in mediation of brain lectin function.