Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lysosomal arylsulfatases A and B of peripheral leukocytes from patients with chronic myelogenous leukemia and from healthy subjects were studied. Two enzyme activities of leukemia cells were significantly higher than those of cells from healthy subjects, irrespective of total and differential counts of leukemic cells. Upon anion-exchange chromatography, the arylsulfatases of chronic myelogenous leukemia cells and normal leukocytes were separated into the basic B enzyme and its anionic variant (B1) and A enzyme. However, the amount of B1 enzyme relative to B enzyme or the activity ratio of B1 enzyme to total arylsulfatase B (B + B1) was higher in chronic myelogenous leukemia cells than in normal cells. The anionic property of the enzyme was found to be due to phosphate groups bound to the carbohydrate moiety of the arylsulfatase, based on the following results. When B1 enzyme was treated with alkaline phosphatase followed by isoelectric focusing, it was changed to a less anionic enzyme with heterogeneous components which are ascribed to phosphodiester groups linked to the heterogeneous carbohydrate moiety of the enzyme; no effect was observed by sialidase treatment. Upon treatment of B1 enzyme with endo-beta-N-acetylglucosaminidase H, which cleaves sugar chains of a high mannose type in glycoproteins, the anionic heterogeneous components were converted to the basic component similar to B enzyme. From our present and previous observations, it can be concluded that the increase of phosphorylated forms of the lysosomal hydrolase represents one characteristic of rapidly proliferating neoplastic cells.
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PMID:Lysosomal arylsulfatases of human leukocytes: increment of phosphorylated B variants in chronic myelogenous leukemia. 613 78

A xylose-based glycosaminoglycan (GAG) core was recently identified at a Ser residue in the linker sequence of a recombinant Fc fusion protein. The linker sequence, G-S-G-G-G-G, and an upstream acidic residue were serving as a substrate for O-xylosyltransferase, resulting in a major glycan composed of Xyl-Gal-Gal-GlcA and other minor intermediates. In this paper, a portion of an unrelated protein was fused to the C-terminus of an IgG Fc domain using the common (G4S) 4 linker repeat. This linker resulted in a heterogenous population of xylose-based glycans all containing at least a core Xyl. Commonly observed glycan structures include GAG-related di-, tri-, tetra-, and penta-saccharides (e.g., Xyl-Gal, Xyl-Gal-Gal, Xyl-Gal-Gal-GlcA, and Xyl-Gal-Gal-GlcA-HexNAc), as well as Xyl-Gal-Neu5Ac. Following alkaline phosphatase or sialidase treatment combined with CID fragmentation, low-level glycans with a mass addition of 79.9 Da were confirmed to be a result of phosphorylated xylose. A minute quantity of phosphorylated GAG pentasaccharides may also be sulfated (also 79.9 Da), possibly at the HexNAc moiety due to non-reactivity to alkaline phosphatase. The xylose moiety may be randomly incorporated in one of the three G-S-G sequence motifs; and the linker peptide shows evidence for multiple additions of xylose at very low levels.
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PMID:O-glycosylation of glycine-serine linkers in recombinant Fc-fusion proteins: attachment of glycosaminoglycans and other intermediates with phosphorylation at the xylose sugar subunit. 2492 72