Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycopolypeptide (1) carrying the beta-D-Gal-(1-->3)-alpha-D-GalNAc unit as a kind model of asialo-type mucin was synthesized through three steps: enzymatic synthesis of p-nitrophenyl disaccharide glycoside, reduction of the p-nitrophenyl group, and coupling of the amino group with the carboxyl group of poly(L-glutamic acid)s (PGA). In a similar manner, glycopolypeptides (2-7) carrying beta-D-Gal-(1-->3)-beta-D-GalNAc, beta-D-Gal-(1-->3)-beta-D-GlcNAc, beta-D-Gal-(1-->6)-alpha-D-GalNAc, beta-D-Gal-(1-->6)-beta-D-GalNAc, alpha-D-GalNAc, and beta-D-GalNAc, respectively, were synthesized as analogous polymers of polymer 1. Glycopolypeptides 8 and 9 as a mimic of sialo-type mucin were further prepared from polymers 1 and 2 as the acceptor of CMP-Neu5Ac by alpha2,3-(O)-sialyltransferase, respectively. Interactions of these glycopolypeptides with lectins were investigated with the double-diffusion test and the hemagglutination-inhibition assay and in terms of an optical biosensor based on surface plasmon resonance. Polymers 1 and 2 reacted strongly with peanut (Arachis hypogaea) agglutinin (PNA) and Agaricus bisporus agglutinin (ABA). On the other hand, polymers 8 and 9 through sialylation from polymers 1 and 2 reacted with ABA, but did not with PNA. Other polymers 3-7 did not show any reactivity for both the lectins. These results show that PNA acts precisely in an exo manner on the beta-D-Gal-(1-->3)-D-GalNAc sequence, while ABA acts in an endo manner. Polymers 6 and 7 substituted with GalNAc reacted strongly with soybean (Glycine max) agglutinin and Vicia villosa agglutinin B4, regardless of the configuration of the glycosidic linkage. The interaction of all polymers with Bauhinia purpurea agglutinin was much stronger than that of the corresponding sugars. Polymers 8 and 9 reacted with wheat germ (Triticum vulgaris) agglutinin (WGA), to which Neu5Ac residues are needed for binding, but polymers 1 and 2 did not. These sugar-substituted glycopolypeptides interacted specifically with the corresponding lectins. Furthermore, polymers 4-7 reacted with WGA, but the corresponding sugars did not. It suggests that the N-acetyl group along the PGA backbone has a cluster effect for WGA. The artificial glycopolypeptides were shown to be useful as tools and probes of carbohydrate recognition and modeling in the analysis of glycoprotein-lectin interactions.
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PMID:Chemoenzymatic synthesis of glycopolypeptides carrying alpha-Neu5Ac-(2-->3)-beta-D-Gal-(1-->3)-alpha-D-GalNAc, beta-D-Gal-(1-->3)-alpha-D-GalNAc, and related compounds and analysis of their specific interactions with lectins. 1109 73

The main objective of this study was to eliminate the hemagglutination activity of an antinutritional factor in soybeans, soybean agglutinin (SBA). A series of experiments was designed to enzymatically modify SBA structure and to use other physical treatments to reduce activity. SBA extract was prepared from soy flour and used as the substrate for all treatments. Deglycosylation by enzyme decreased activity of SBA by 21%, but not to the level of denaturation by heat or by denaturing reagents (47-77% residual activity). Single enzymes, such as trypsin, chymotrypsin, thermolysin, and endoproteinase Glu-C, did not hydrolyze native SBA, but they hydrolyzed heat- or organic solute-denatured SBA. Even after hydrolysis, SBA still had 44-62% residual activity. Combinations of enzymes with thermolysin fully deactivated heat- or guanidine hydrochloride- and urea-treated SBA. Pepsin and pancreatin hydrolysis fully deactivated not only heated but also native SBA. Tea polyphenols, metal ions, and chelating agents were also tested, and they showed no significant effect on SBA activity. N-Acetylgalactosamine-agarose beads specifically but not fully removed SBA from the soy protein mixture. In general, SBA needs to be denatured first for an effective enzymatic hydrolysis, and multiple enzymes are needed to fully deactivate SBA. Pepsin and pancreatin treatment showed great promise in fully reducing SBA activity, and it would be further tested using soy flour as a model system.
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PMID:Deactivation of soybean agglutinin by enzymatic and other physical treatments. 2094 44