Browsing by Author "KANNAN, VM"

Now showing 1 - 3 of 3
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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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    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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    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.