Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.16.3.1 (ceruloplasmin)
 5,074 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inhibition of pig NK cell activity by asialooligosaccharides (aOS) isolated from human serum glycoproteins was investigated. Train-tennary aOS (aOSIII) of ceruloplasmin was found to be the most potent inhibitor up to the concentration 0.1 micrograms/ml, which is in agreement with its highly specific binding to NK-activity-enriched pig lymphocytes (with a morphology similar to human large granular lymphocytes (LGL]. Only lectins with the specificity to Gal(beta 1----4)GlcNAc or Gal(beta 1----3)GalNAc structures exhibited inhibition of NK cytotoxicity. F(ab)2 fragments of rabbit antibodies against pig spleen membrane lectin cross-reacting with the pig liver membrane lectin completely inhibited NK activity when preincubated with the effectors or present in the incubation mixture during the assay. These data suggest that lectin receptors on cells of pig NK-activity-enriched fraction specific for aOSIII and antigenically related to membrane lectins isolated from pig spleen and liver, are involved in the NK recognition of several xenogeneic targets.
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PMID:Lactosamine type asialooligosaccharide recognition in NK cytotoxicity. 372 39

We have examined the kinetics of binding and uptake of iodinated glycoproteins and glycopeptides bearing terminal Gal or GalNAc moieties in an isolated rat hepatocyte system. Asparagine-linked, triantennary complex oligosaccharides with three terminal Gal residues are endocytosed with the same kinetics as asialo-orosomucoid, whereas biantennary, complex oligosaccharides with one or two terminal Gal residues are not endocytosed Glycopeptides bearing as few as four O-glycosidically-linked Gal beta 1, 3GalNAc or GalNAc moieties are also rapidly endocytosed, while glycopeptides with one or two more closely spaced moieties are not endocytosed. All the endocytosable glycoproteins and glycopeptides have similar apparent dissociation constants and a similar number of binding sites on the surface of the intact hepatocyte. The ligand-binding properties of the receptor in the plasma membrane of intact cells differ from those of the solubilized receptor, suggesting that interaction with other as yet undefined cellular components confers the ability to discriminate among closely related oligosaccharide structures. This is consistent with a model in which only glycopeptides bearing terminal Gal or GalNAc residues that fall within a restricted spatial relationship can induce a conformational alteration in the receptor which is required for uptake to occur. The endocytosis of a number of glycoproteins such as human asialo-ceruloplasmin can be accounted for by the presence of a single, complex oligosaccharide with the appropriate structure.
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PMID:Galactose and N-acetylgalactosamine-specific endocytosis of glycopeptides by isolated rat hepatocytes. 744 75