Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

P-selectin on platelets and endothelial cells and E-selectin on endothelial cells are leukocyte receptors that recognize lineage-specific carbohydrates on neutrophils and monocytes. The proposed ligands for these receptors contain the Le(x) core and sialic acid. Since other investigators have shown that both E-selectin and P-selectin bind to sialylated Le(x), we evaluated whether E-selectin and P-selectin recognize the same counter-receptor on leukocytes. The interaction of HL60 cells with Chinese hamster ovary (CHO) cells expressing P-selectin or E-selectin was studied. To determine whether a protein component is required in addition to sialyl Le(x) for either P-selectin or E-selectin recognition, HL60 cells or neutrophils were digested with proteases, including chymotrypsin, elastase, proteinase Glu-C, ficin, papain, or thermolysin. Cells treated with these proteases bound E-selectin but not P-selectin. Fucosidase or neuraminidase treatment of HL60 cells markedly decreased binding to both E-selectin- and P-selectin-expressing CHO cells. Growth of HL60 cells in tunicamycin inhibited the ability of these cells to support P-selectin-mediated binding and, to a lesser extent, E-selectin-mediated binding. Purified P-selectin inhibited CHO:P-selectin binding to HL60 cells, but incompletely inhibited CHO:E-selectin binding to HL60 cells. However, purified soluble E-selectin inhibited CHO:P-selectin and CHO:E-selectin binding to HL60 cells equivalently and completely. COS cells, unable to bind to E-selectin or P-selectin, bound E-selectin but not P-selectin upon transfection with alpha-1,3-fucosyltransferase or alpha-1,3/1,4-fucosyltransferase. Similarly, LEC 11 cells expressing sialyl Le(x) bound E-selectin- but not P-selectin-expressing CHO cells. Sambucus nigra lectin, specific for the sialyl-2,6 beta Gal/GalNAc linkage, inhibited P-selectin but not E-selectin binding to HL60 cells. Although sialic acid and Le(x) are components of the P-selectin ligand and the E-selectin ligand, these results indicate that the ligands are related, having overlapping specificities, but are structurally distinct. A protein component containing sialyl Le(x) in proximity to sialyl-2,6 beta Gal structures on the P-selectin ligand may contribute to its specificity for P-selectin.
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PMID:P-selectin and E-selectin. Distinct but overlapping leukocyte ligand specificities. 137 36

A novel form of free human chorionic gonadotrophin beta-subunit (hCG beta) was found in serum from ElBre, a woman with epidermoid carcinoma of unknown origin. ElBre hCG beta was larger than standard (pregnancy urine) hCG beta when analysed by gel chromatography (apparent molecular weight 54 000 vs 44 000). This size difference appeared to be due to a larger carboxyterminal extension (CTE) of ElBre hCG beta since thermolysin cleavage of the CTE from standard hCG beta and Elbre hCG beta yielded core products of the same size. Oligosaccharides, O-linked to serine or threonine, were present in ElBre hCG beta, presumably on its CTE as judged by the complete binding of desialylated ElBre hCG beta to immobilized peanut agglutinin (this lectin is specific for terminal galactose linked beta 1----3 to N-acetylgalactosamine, a disaccharide exposed after desialylation of the O-linked oligosaccharides of standard hCG beta). ElBre hCG beta, however, was incompletely recognized by antisera specific for the CTE of standard hCG beta, especially the carbohydrate-sensitive antiserum R141. The O-linked oligosaccharides of standard hCG beta are heterogeneous in size; 13% are of the largest (hexasaccharide) form. In contrast, over 50% of the O-linked oligosaccharides in hCG beta from the JAr choriocarcinoma cell line are hexasaccharides. Like desialylated ElBre hCG beta, desialylated JAr hCG beta bound completely to peanut agglutinin, but was incompletely recognized by antisera to the hCG beta-CTE. Furthermore, JAr hCG beta was intermediate in size between standard hCG beta and ElBre hCG beta when analysed by gel chromatography (apparent molecular weight 49 000).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A novel form of ectopic human chorionic gonadotrophin beta-subunit in the serum of a woman with epidermoid cancer. 241 52

35SO4(2-)- or [3H]GlcN-labeled heavy proteochondroitin sulfate was isolated from monolayer cultures of chondrocytes from the zones of dividing, elongated, and hypertrophying cells of chick embryo tibias, and the keratan sulfate (KS) component was characterized. The KS glycopeptides remaining after digestion of the proteoglycans with thermolysin and chondroitinases were isolated and depolymerized by hydrazinolysis and nitrous acid cleavage. The resulting KS disaccharides had nonreducing terminal D-galactose (Gal) residues and reducing terminal anhydro-D-mannose (AMan) residues. The KS fractions from all cultures had identical disaccharide compositions, with 18-20% Gal----AMan, 72-79% Gal----AMan(6-SO4), and 7-9% Gal(6-SO4)----AMan(6-SO4). The ratios of chondroitin sulfate (CS) to KS synthesized by cultures of dividing, elongated, and hypertrophied chondrocytes were 15, 27, and 30, respectively. Approximately 30% of the CS chains of the proteochondroitin sulfate in the cell matrix pools had nonreducing terminal GalNAc(4,6-diSO4) residues, but none of the CS chains in the proteochondroitin sulfate recovered from the culture medium pools were terminated with these residues.
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PMID:Structural changes in the large proteoglycan in differentiating chondrocytes from the chick embryo tibiotarsus. 406 3

Immunoglobulin A1 (IgA1) from normal human serum is known to have O-linked sugar chains, sialylated Galbeta1,3GalNAc, in the hinge portion. In order to reduce the microheterogenity of the sugar chain, the hinge glycopeptide prepared from IgA1 was sequentially treated with neuraminidase and beta-galactosidase. The asialo-, agalacto-hinge glycopeptide (HGP-SG) composed of a 33-mer peptide (HP33) and N-acetylgalactosamine (GalNAc) residues was obtained. The HGP-SG was separated into three major peaks, A, B and C, by high-performance liquid chromatography (HPLC). Each glycopeptide fraction was further separated by capillary electrophoresis (CE). Peaks A, B and C with HPLC abundantly contained HP33 bearing five and six N-acetylgalactosamine residues (HGP33-5,6GN), HGP33-4,5GN and HGP33-3,4GN, respectively. Among these glycopeptide peaks, only the HGP33-5GN peak was partly split into two peaks based on the CE analysis - HGP33-5GN-alpha and -beta. The glycopeptide, HGP25-5GN shortened by the thermolysin digest of HGP33-SG was also well separated into the alpha and beta forms by CE analysis. No differences in their mass and peptide portion were observed between HGP25-5GN-alpha and -beta. Therefore, the obtained result might indicate that HGP25-5GN-alpha was an isomer of HGP25-5GN-beta differing in its stereospecific structure of the peptide portion and/or the attachment site of the GalNAc residue.
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PMID:Mutual separation of hinge-glycopeptide isomers bearing five N-acetylgalactosamine residues from normal human serum immunoglobulin A1 by capillary electrophoresis. 1040 3

To determine the epitopic structure for an anti-Siaalpha2-6GalNAcalpha-Ser/Thr (anti-sialyl Tn) monoclonal antibody, MLS 132, ovine submaxillary mucin (OSM) was digested with the combination of trypsin and thermolysin and the digest fractionated by immunoaffinity column chromatography and HPLC. From tryptic digest, a major glycopeptide designated as T3 was obtained as an immunoaffinity column-bound fraction. On solid-phase radioimmunoassay, it was found that T3 exhibited strong immunoreactivity with MLS 132. On treatment with thermolysin, T3 was converted into about 50 fragments, as found on fractionation by HPLC. Several of them were strongly immunoreactive and had the same amino acid sequence, i.e. Phe-Ser*-Gly-Glu-Thr*-Ser*-Thr*-Thr*-Val-Ile-Ser*-Gly-Thr*-Asn-Val, where asterisks denote the sites of attachment of carbohydrate. Of these, one was fully sialylated, the others having one Ser or Thr with unsialylated GalNAc attached. Results of analyses of the carbohydrate attached in these glycopeptides led us to postulate that a cluster composed of four sialyl Tn antigens is the essential epitopic structure for MLS 132.
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PMID:Binding characteristics of an anti-Siaalpha2-6GalNAcalpha-Ser/Thr (sialyl Tn) monoclonal antibody (MLS 132). 1042 83

The main objective of this study was to eliminate the hemagglutination activity of an antinutritional factor in soybeans, soybean agglutinin (SBA). A series of experiments was designed to enzymatically modify SBA structure and to use other physical treatments to reduce activity. SBA extract was prepared from soy flour and used as the substrate for all treatments. Deglycosylation by enzyme decreased activity of SBA by 21%, but not to the level of denaturation by heat or by denaturing reagents (47-77% residual activity). Single enzymes, such as trypsin, chymotrypsin, thermolysin, and endoproteinase Glu-C, did not hydrolyze native SBA, but they hydrolyzed heat- or organic solute-denatured SBA. Even after hydrolysis, SBA still had 44-62% residual activity. Combinations of enzymes with thermolysin fully deactivated heat- or guanidine hydrochloride- and urea-treated SBA. Pepsin and pancreatin hydrolysis fully deactivated not only heated but also native SBA. Tea polyphenols, metal ions, and chelating agents were also tested, and they showed no significant effect on SBA activity. N-Acetylgalactosamine-agarose beads specifically but not fully removed SBA from the soy protein mixture. In general, SBA needs to be denatured first for an effective enzymatic hydrolysis, and multiple enzymes are needed to fully deactivate SBA. Pepsin and pancreatin treatment showed great promise in fully reducing SBA activity, and it would be further tested using soy flour as a model system.
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PMID:Deactivation of soybean agglutinin by enzymatic and other physical treatments. 2094 44