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)

Gc-globulin or group-specific component, also known as the vitamin D-binding protein, was investigated by the combined use of electrofocusing and immunofixation. Serum of the Gc 2-2 type was found to contain a single protein band whereas serum of the Gc 1-1 type shows two bands with a lower isoelectric point. The Gc 1-2 type contains all three bands known as Gc-2 (pI 5.10), Gc-1Slow (pI 5.03), and Gc-1Fast (pI 4.95). Each apoprotein shows an anodal shift of about 0.07 pH unit after incubation with an excess of 25-hydroxycholecalciferol. After treatment with sialidase Gc-1Fast focuses in the position of Gc-1Slow, whereas the position of Gc-2 remains unchanged.
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PMID:The heterogeneity of human Gc-globulin. 7 72

The Hodgkin-associated Ki-1 antigen occurs in two different molecular forms. The 120-kDa membrane-associated form is a phosphorylated glycoprotein, which is derived from a non-phosphorylated intracellular 84-kDa apoprotein that is co-translationally N-glycosylated with a carbohydrate portion of 6 kDa. The other form of the Ki-1 antigen is a non-glycosylated phosphoprotein of 57 kDa which only occurs intracellularly. Both forms of the antigen are phosphorylated at serine residues. Enzymatic cleavage with sialidase reduced the 120-kDa membrane antigen by about 15 kDa, while its 90-kDa precursor and the 57-kDa intracellular form of the Ki-1 antigen remained unaltered. Pulse-chase experiments revealed that the 57-kDa and 90/120-kDa molecules are synthesized independently of each other. Four to eight hours after synthesis, the degradation of the 120-kDa molecule to a 105-kDa membrane-associated intermediate begins. This is further processed and appears in the cell supernate as a 90-kDa molecule. Hodgkin's disease-derived, Epstein-Barr virus-transformed cell lines and the acute T cell leukemia line MOLT-4 contain both forms of the Ki-1 antigen, whereas only the 57-kDa intracellular antigen is expressed in U266/B1 myeloma cells, in the Burkitt lymphoma cell lines Raji and Daudi and in acute promyelocytic HL-60 leukemia cells.
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PMID:The Hodgkin-associated Ki-1 antigen exists in an intracellular and a membrane-bound form. 254 29

The colon carcinoma cell line COLO 205 has earlier been shown to express and secrete two mucin-type glycoproteins, the leukocyte-associated sialoglycoprotein CD43 or leukosialin (named L-CanAg) and the MUC1 mucin (named H-CanAg). Both glycoproteins carry sialyl-Lewis a epitopes and could bind transfected COS cells expressing E-selectin in a Ca(2+)- and E-selectin-dependent way. Using the monoclonal antibodies C50, C241 (both against sialyl-Lewis a), and CSLEX1 (against sialyl-Lewis x), the MUC1 mucin was shown to express both sialyl-Lewis a and sialyl-Lewis x epitopes, while the CD43 mucin expressed sialyl-Lewis a and almost no sialyl-Lewis x epitopes. These two secreted glycoproteins could inhibit human polymorphonuclear leukocyte or HL-60 cell adhesion to E-selectin-transfected COS cells or IL-1 beta-stimulated human endothelial cells in vitro. The inhibitory efficiency of the MUC1 mucin was 5-10 times larger than that of the CD43 mucin, when studied on endothelial cells and comparable amounts of sample were used. Removing the sialic acids from the MUC1 or CD43 mucins by sialidase treatment abolished the inhibitory effect. Monoclonal antibodies against sialyl-Lewis a greatly and equally inhibited the binding of the MUC1 or CD43 mucins, whereas an antibody against sialyl-Lewis x (CSLEX1) showed almost no inhibitory effect. The result proposes that the sialyl-Lewis a epitope on at least some mucin-type molecules bind E-selectin better than sialyl-Lewis x and that the potency of tumor-secreted mucins to interfere with leukocyte attachment to E-selectin could be dependent on the apoprotein size or its presentation of the carbohydrate epitopes.
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PMID:Comparison of sialyl-Lewis a-carrying CD43 and MUC1 mucins secreted from a colon carcinoma cell line for E-selectin binding and inhibition of leukocyte adhesion. 914 14