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

Jelly coat of sea-urchin eggs consists of polysaccharides and glycoproteins. Some properties of jelly coat have already been investigated, but not histochemically. The oogenesis in Paracentrotus lividus was studied histologically and the oocytes were classified into six different stages. The extracellular jelly appeared first around the growing oocytes II which remained attached to the germinal epithelium. The jelly became thicker when the oocyte approached maturation. Histochemical analysis revealed that the jelly consists of mucopolysaccharide-protein-complexes. The polysaccharide component is composed of both neutral and acid mucopolysaccharides. The former are amylase-resistant. The acid mucopolysaccharides contain both carboxyl and sulfate groups, which are in close proximity to vicinal hydroxyl groups. Sulfated mucopolysaccharide is hyaluronidase-resistant. Sialic acid could not be clearly demonstrated, because it seems to be resistant to neuraminidase. Pepsin digestion indicated the masking of acidic groups by proteins which compete with basic dyes (Alcian blue, Azure A, coriphosphine etc.). Proteolytic digestion enhanced dye-binding ability of jelly, but removed also some of the periodate-reactive mucosubstances. Also a protein component could be demonstrated histochemically. No histochemical difference between jelly coat of oocytes and that of eggs has been found. The possible molecular structure of jelly coat is discussed.
 ...
PMID:Histochemical studies of jelly coat of sea-urchin eggs during oogenesis. 621 73

Sera containing the rare alkaline phosphatase-immunoglobulin G complex were studied to try to determine the type of interaction involved. Pepsin and papain digestion of immunoglobulin G showed that alkaline phosphatase was attached to the F(ab')2 region of the immunoglobulin molecule and not to the Fc region. Sialic acid did not play a role in this attachment. Attempts to generate the complex in vitro using polyclonal immunoglobulin, and attempts to dissociate the complex is an immune complex in vitro, were both unsuccessful. It is concluded that the complex is an immune complex formed by antibody-antigen reaction in the circulation, and consists of two molecules of monovalent alkaline phosphatase associated with one molecule of divalent immunoglobulin G.
 ...
PMID:Site of alkaline phosphatase attachment in alkaline phosphatase-immunoglobulin G complexes. 678 2

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.
 ...
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

Highly water-soluble glycopolymers with poly(alpha-L-glutamic acid) (PGA) backbones carrying multivalent sialyl oligosaccharides units were chemoenzymatically synthesized as polymeric inhibitors of infection by human influenza viruses. p-Aminophenyl disaccharide glycosides were coupled with gamma-carboxyl groups of PGA side chains and enzymatically converted to Neu5Acalpha2-3Galbeta1-4GlcNAcbeta-, Neu5Acalpha2-6Galbeta1-4GlcNAcbeta-, Neu5Acalpha2-3Galbeta1-3GalNAcalpha-, and Neu5Acalpha2-3Galbeta1-3GalNAcbeta- units, respectively, by alpha2,3- or alpha2,6-sialytransferases. The glycopolymers synthesized were used for neutralization of human influenza A and B virus infection as assessed by measurement of the degree of cytopathic inhibitory effect in virus-infected MDCK cells. Among the glycopolymers tested, alpha2,6-sialo-PGA with a high molecular weight (260 kDa) most significantly inhibited infection by an influenza A virus, strain A/Memphis/1/71 (H3N2), which predominantly binds to alpha2-6 Neu5Ac residue. The alpha2,6-sialo-PGA also inhibited infection by an influenza B virus, B/Lee/40. The binding preference of viruses to terminal sialic acids was affected by core determinants of the sugar chain, Galbeta1-4GlcNAcbeta- or Galbeta1-3GalNAcalpha/beta- units. Inhibition of infection by viruses was remarkably enhanced by increasing the molecular weight and sialic acid content of glycopolymers.
 ...
PMID:Chemoenzymatic synthesis and application of glycopolymers containing multivalent sialyloligosaccharides with a poly(L-glutamic acid) backbone for inhibition of infection by influenza viruses. 1262 82

The immunomodulatory effect of GMP and its derivates on the cell proliferative response of human macrophagelike cell, U937, and its effect on phagocytic activities via incorporation of fluorescence beads were studied. GMP was found to be a potent immunoenhancer at low concentrations, significantly enhancing the proliferation and phagocytic activities of U937. The modulatory function could be radically altered by enzymatic treatments. Pepsin digestion significantly enhanced the degree of cell proliferation and phagocytic activities, whereas trypsin had no significant effect. The immunoenhancing effects decreased significantly after sialidase treatment; however, more than 70% of activity was retained after treatment. GMP with different carbohydrate chains was shown to possess different modulatory capabilities. Sialic acid-rich GMP fractions showed an enhanced response. These findings indicate that both the carbohydrate chains compositions, including the terminal sialic acids and the polypeptide portions of GMP, are essential for the stimulatory effects of GMP on cell proliferation and phagocytic activities of U937.
 ...
PMID:Immunoenhancing effects of bovine glycomacropeptide and its derivatives on the proliferative response and phagocytic activities of human macrophagelike cells, U937. 1511 79