Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous histochemical and biochemical studies have documented the presence of carbohydrate-containing molecules in the retinal interphotoreceptor matrix (IPM). The lectin peanut agglutinin (PNA), which preferentially binds galactose-containing carbohydrates, especially galactose-galactosamine linkages, selectively labels cone photoreceptor-associated domains of the IPM ('cone matrix sheaths') in a variety of vertebrate retinas. In the studies described here, the nature of these PNA-binding components was investigated by monitoring the effects of proteolytic and glycosidic enzymes on binding of the lectin in the retina and IPM. All proteolytic enzymes tested cause a marked reduction in PNA-binding to cone matrix sheaths, suggesting that proteinaceous components are important to their organization. Exposure to O-glycanase, but not N-glycanase, markedly reduces binding of PNA to cone matrix sheaths indicating that O-linked oligosaccharides are probably responsible for its binding. Galactose oxidase treatment reduces PNA-binding throughout the retina and IPM, confirming that galactose moieties are involved in its binding. beta-Galactosidase (either before or after neuraminidase treatment) does not alter the pattern of PNA binding, suggesting that neither terminal nor penultimate beta-linked galactose residues constitute a major proportion of the lectin's binding sites in the retina. Neuraminidase treatment markedly increases the density and distribution of PNA binding throughout the retina and IPM, however, this effect appears to be, at least in part, the result of the binding of the lectin to neuraminidase molecules that become associated with tissue sections in addition to binding to carbohydrate groups unmasked by desialation. Exposure to chondroitinases causes disruption of the morphological integrity of cone matrix sheaths and slight diminution of PNA binding. Other enzymes acting on common constituents of extracellular matrices do not have similar effects. Taken together, these observations suggest that PNA-binding to cone matrix sheaths is due to the presence of glycoconjugates with galactose-containing, O-linked oligosaccharide chains.
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PMID:Enzymatic characterization of peanut agglutinin-binding components in the retinal interphotoreceptor matrix. 310 30

Detailed structures of N-linked oligosaccharides of Defibrase, a highly active thrombin like enzyme (TLE) purified from the venom of Agkistrodon acutus, were successfully characterized using MALDI-TOF mass spectrometry in combination with sequential exoglycosidase digestion. Monosaccharide composition analysis was performed by high performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Galactose(Gal), mannose(Man), fucose(Fuc), N-acetylglucosamine (GlcNAc), and sialic acid (Neu5Ac) was detected and the total carbohydrate content was about 19.4% (w/w). The N-linked oligosaccharides were released by treatment with PNGase F, fluorescent labeled with 2-aminobenzamide, and fractionated by high performance liquid chromatography (HPLC). The main oligosaccharide fractions were collected and further digested with an array of exoglycosidase mixtures, and subsequent MALDI TOF MS analysis of the resulting products yielded information about structural features of the oligosaccharide. The combined data revealed the presence of five distinct oligosaccharide structures in Defibrase, which are mainly complex or hybrid type, with a small amount of oligomannosidic type. The complex type oligosaccharides are mostly tri-or bi-antennary and the hybrid oligosaccharides are all bi-antennary. Most oligosaccharides are also found to be fucosylated.
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PMID:Structural characterization of N-linked oligosaccharides of Defibrase from Agkistrodon acutus by sequential exoglycosidase digestion and MALDI-TOF mass spectrometry. 1980 Sep 8