Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.11 (CD10)
 9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The properties of two purified peptidases derived from the intestinal brush border membrane of the rat have been investigated. The pH optima, heat stabilities, substrate specificities, and metal ion requirements of the two enzymes and the effects of inhibitors on their activities were nearly identical. The isoenzymes catalyzed the hydrolysis of a wide range of peptides containing from 2 to 8 amino acid residues. The enzymes are aminopeptidases; no evidence for carboxypeptidase or endopeptidase activity was found. For hydrolysis, there appears to be an absolute requirement for an L-amino acid at the NH2-terminus of the peptide substrate. There was a similar but less absolute requirement for the penultimate NH2-terminal amino acid. Thus, although peptides of the type L-aminoacyl-L-proline, L-aminoacyl-L-prolyl-(L-amino acid)n, or L-aminoacyl-D-amino acid were not hydrolyzed, L-leucyl-beta-naphthylamide could be utilized as a substrate. The enzymes appeared to be metalloenzymes in that metal ion-chelating agents could inhibit their activities. Co2+ partially restored the activities lost by chelation. Immunodiffusion studies showed that the two enzymes were immunologically identical. The antipeptidase antisera were specific for the enzymes and did not react with other constituents of the intestinal cell. Both enzymes have binding sites for the lectin phytohemagglutinin which recognizes N-acetylgalactosamine residues located at or near the terminal positions of glycoprotein carbohydrate chains. Both the lectin and the antibodies inhibited enzyme activities, but the mechanisms of inhibition appeared to be different.
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PMID:Rat intestinal brush border membrane peptidases. II. Enzymatic properties, immunochemistry, and interactions with lectins of two different forms of the enzyme. 0 46

Renal tumours were induced in dietary-primed rats by injection of dimethylnitrosamine. Control and tumour tissue was excised at varying periods and maintained in short-term organ culture in the presence of 3H- or 14C-fucose. The plasma membranes were then isolated, and the isotopic profiles of normal kidney and renal tumour membrane proteins were established, using polyacrylamide-gel electrophoresis in dodecyl sulphate. Several fucose-containing glycoproteins of the plasma membranes were found to alter upon neoplastic transformation: 4 increased and 3 decreased. The probable identity of 2 of these proteins is indicated: alpha-foetoprotein is one of the glycoproteins which increased, whereas neutral endopeptidase decreased in the tumour membranes. Fluorescein-labelled lectin binding by the kidney tissue was also found to alter upon transformation. The most marked changes were an increase in sialic acid (neuraminidase-sensitive) and galactosamine (Ricinus communis agglutinin Type I) in the nuclei of some neoplastic cells and some hyperplastic-tubule cells.
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PMID:Saccharide alterations in rat kidney associated with malignant transformation by injection of dimethylnitrosamine. 65

Induction of arthritis in rats with Freund's complete adjuvant was accompanied by a distinctive alteration of concanavalin A (Con-A) reactivity in their serum proteins in which the concentrations of selected Con-A reactive proteins were significantly higher when compared to healthy rats. To assess if the observed increase in Con-A reactivity of specific serum proteins reflects an increase in carbohydrate moieties in these proteins in addition to an increase in their protein concentrations, a heme binding serum glycoprotein, hemopexin, also an acute phase reactant, was selected as a marker protein. Hemopexin was purified to apparent homogeneity from pools of serum samples derived from rats with yeast induced inflammation, a monospecific polyclonal antibody was prepared and was used for immunoblot analysis. It was noted that the concentration of hemopexin increased in rats with adjuvant induced arthritis; however, its concentration fell to normal levels after administration with a newly synthesized drug, bindarit, (2-[(1-benzyl-indazol-3-yl)methoxy]-2-methyl propionic acid, C19H20N2O3. Hemopexin was micropurified individually from healthy rats, adjuvant induced arthritic rats, and adjuvant arthritic rats treated with bindarit, cleaved with a Glu-C endopeptidase, Staphylococcus aureus protease V8, and the resultant peptide fragments resolved by SDS-PAGE and examined by silver staining, Coomassie blue staining, and lectin blots using Con-A. It was subsequently noted that hemopexin isolated from adjuvant induced arthritic rats showed a significant increase in Con-A reactivity in selected peptide fragments and that such an increase in glycosylation could be reversed to a pattern similar to healthy rats following treatment with bindarit.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Abnormal glycosylation of hemopexin in arthritic rats can be blocked by bindarit. 128 32

A panel of cell-type specific monoclonal and polyclonal antibodies and lectins was used to examine the early, morphologically epithelial outgrowth of rat renal glomerular cells in culture. The cell type-specific reactivity of the monoclonal antibodies has been previously verified on tissue sections of rat kidneys at light and electron microscopic levels. Morphologically distinct epithelial cells grew out from the isolated glomeruli within 3 days in culture, followed by the growth of morphologically typical stellate mesangial-like cells. Endothelial and mesangial cells were positively identified from the early cultures (up to 10 days) with antibodies to a 350 kD protein, dipeptidyl peptidase IV, podocalyxin, factor VIII, OX-43 and with Bandeiraea simplicifolia (BS-I B4) lectin, and with antibodies to smooth muscle actin, desmin, Thy1.1 antigens and with Ricinus communis (RCA-1) lectin, respectively. The antibodies recognizing podocytes in vivo (antipodocalyxin, anti-O-acetyl GD3 ganglioside, anti-gp330, anti-C3b complement receptor, anti-vimentin and anti-CALLA) consistently failed to bind to the predominant epithelial cells in early cultures, although these antibodies readily bound to the cells of the intact glomeruli remaining in culture. The attempts to augment the expression of cell-type specific epitopes by culturing glomeruli on various matrices or by enriching the medium with various growth factors, failed to induce podocytic epitopes on the growing epithelial cells. Glomeruli from newborn rats cultured in vitro, but were also constantly negative for the markers of podocytes. In addition, we cultured glomerular-like bodies from in vitro were induced metanephric mesenchymes but failed to obtain evidence of growing podocytes. However, the epithelial cells reacted with antibodies to thrombospondin and cytokeratin that react with the parietal epithelium of glomeruli on tissue sections. The results show that early glomerular cultures consist of mesangial, endothelial and presumably parietal epithelial cells readily identifiable by immunocytochemical methods. No podocytes could be grown under the various growth conditions tested. This suggests that glomerular podocytes are effectively growth arrested and call for new approaches to obtain these cells in culture.
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PMID:Rat glomerular cells do not express podocytic markers when cultured in vitro. 175 4

The amino-acid sequence of a lectin isolated from the coelomic fluid of the acorn barnacle Megabalanus rosa has been determined. The lectin (Mr 140,000) is a multimeric protein whose subunit consists of 173 amino acids and one carbohydrate chain attached to Asn-39. The amino-acid sequence was determined by the manual sequencing of peptides derived from the protein by digestion with Staphylococcus aureus V8 proteinase, lysine endopeptidase and chymotrypsin, as well as fragments produced by cleavage with cyanogen bromide. The amino-acid sequence of the lectin was compared with the sequence of one (Mr 64,000) of the multiple lectins of M. rosa. They are distinct molecules in spite of a significant homology in their amino-acid sequences. The amino-acid sequence includes some regions homologous to those in other invertebrate lectins, such as sea urchin and flesh fly lectins, and vertebrate lectins. This is the first report to show the amino-acid sequence of multiple lectins isolated from an invertebrate.
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PMID:The amino-acid sequence of multiple lectins of the acorn barnacle Megabalanus rosa and its homology with animal lectins. 235

Antiserum to epithelial membrane antigen and three monoclonal antibodies (MAb) to milk-fat globule membranes immunocytochemically stain only epithelial cells, whereas a fourth reacts also with myoepithelial cells in inter- and intralobular ducts of human breast. Staining with peanut lectin shows a gradual increase for epithelial cells, from little or no staining in ducts through variable staining in ductules to intense staining in secretory alveoli. Antisera and MAb to vimentin, smooth-muscle actin, MAb to the common acute lymphoblastic leukemia antigen and to a glycoprotein of 135 KD stain myoepithelial cells in main ducts, but this staining is reduced in inter- and intralobular ducts and ductules. MAb to epithelial-specific keratin 18 stain a minor population of ductal epithelial cells, the major population of epithelial cells in interlobular (ILD) and extralobular terminal ducts (ETD), and epithelial cells in a minority of ductules. In lactating glands most epithelial cells in ductules are stained, but the alveolar and myoepithelial cells are unstained. Keratin MAb PKK2 and LP34 strongly stain myoepithelial cells, but only a minor population of epithelial cells in main ducts. However, these MAb stain principally the epithelial cells in ILD, ETD, and a minority of ductules. In lactating glands most epithelial cells are stained in ductules, but the myoepithelial and not the alveolar cells are stained intensely in secretory lobules. It is suggested that the unusual staining pattern of cells found principally in the ILD, ETD, and some ductules may represent regions of growth and/or subpopulation(s) of cells intermediate between epithelial and myoepithelial cells.
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PMID:Immunocytochemical identification of cell types in human mammary gland: variations in cellular markers are dependent on glandular topography and differentiation. 247 25

We investigated the ability of isolated human colonic epithelial cells to express the common acute lymphoblastic leukemia antigen (CALLA), the transferrin receptor, and the 4F2 antigen in response to different types of stimuli. The expression of these markers was assessed by immunofluorescence using monoclonal antibodies. Thirty-two percent of freshly isolated colonic epithelial cells from actively inflamed mucosa of patients with inflammatory bowel disease expressed the 4F2 antigen, 28% the transferrin receptor, and 13% the CALLA. Normal colonic epithelial cells were cultured and the kinetics of expression of the three antigens was studied. A significant increase in the expression of the three markers was observed throughout the culture period in response to the lectin phytohemagglutinin and the epidermal growth factor. The kinetics of expression of the 4F2 antigen and the CALLA after lectin stimulation appeared to differ from that observed after epidermal growth factor. At the end of the cultures one-third of the cells expressed the 4F2 antigen and the transferrin receptor, whereas one-fifth were positive for CALLA. Thus, after these cultures the expression of the three markers was quantitatively similar to that observed with freshly isolated cells from inflamed mucosa. gamma-Interferon markedly induced the 4F2 antigen but had no effect on the transferrin receptor and the CALLA. These data demonstrate that colonic epithelium is capable of expressing the 4F2 antigen and the CALLA in association with the transferrin receptor.
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PMID:Ability of human colonic epithelium to express the 4F2 antigen, the common acute lymphoblastic leukemia antigen, and the transferrin receptor. Studies in inflammatory bowel disease and after in vitro exposure to different stimuli. 253 Nov

Parenchymal organoidal structures that were obtained from collagenase digestion of reduction mammoplasty specimens of apparently normal human breasts have been grown in short-term primary cultures, either on plastic or on floating gels of polymerized rat-tail collagen. Three morphologically distinct major cell types are readily observed in both systems: cuboidal cells, which occupy apical positions on collagen gels; larger, epithelioid, or basal cells on gels; and elongated cells which penetrate into the gel. In addition, a fourth cell type, that of large, flat cell, is observed less readily by phase contrast microscopy on the surface of cultures grown on plastic. Immunofluorescent and immunocytochemical staining of cultures on plastic or histologic sections of cultures on gels have been undertaken with antisera and other histochemical reagents that stain the different parenchymal cell types in vivo. Thus antisera to epithelial membrane antigen(s), monoclonal antibodies (MABs) to the defatted mammary milk fat globule membrane, peanut lectin, and keratin MAB LE61, which preferentially stain the epithelial cells of ducts in vivo, also stain the cuboidal/apical cells in vitro. The large, flat cells are stained intensely by the first three reagents but not by the last one. Antisera to collagen IV, laminin, fibronectin, actin, keratin MAB LP34, MABs to the common acute lymphoblastic leukemia antigen, and MAB LICR-LON-23.10, which showed enhanced staining for the ductal myoepithelial cells in vivo, also stain the epithelioid/elongated cells in vitro. However, the effect of the last four reagents is reduced considerably in most elongated cells, and MAB LP34 stains the large, flat cells intensely. Heterogeneous cells of intermediate morphologies and staining patterns between the cuboidal cells and large, flat cells are related to mammary epithelial cells. whereas the large epithelioid/elongated cells have some characteristics of myoepithelial cells, and that intermediate forms may exist in culture between the two parenchymal cell types.
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PMID:Characterization of human mammary cell types in primary culture: immunofluorescent and immunocytochemical indicators of cellular heterogeneity. 264 83

A protease of molecular weight 29,000 was isolated and purified using ammonium sulphate precipitation, lentil lectin-Sepharose affinity chromatography and DEAE-5PW ion-exchange chromatography. The protease had an unusual amino acid composition including 5% serine, 6% proline and 20% tyrosine. It was a glycoprotein containing 12-15% carbohydrate by weight. Activity was optimal at 40-45 degrees C using [3H]-acetyl casein substrate and at 40-55 degrees C using [3H]-acetyl enamel protein substrate. It was irreversibly denatured at 80 degrees C and above. With [3H]-acetyl casein the pH optimum was 8.0-8.5 and with [3H]-acetyl enamel protein it was 6.0-8.0. There was no activity below pH 5.0, and irreversible denaturation occurred at pH 4.0 and below. No autodegradation occurred with storage at 4 degrees C for 30 days at pH 7.0. Phenylmethylsulphonyl fluoride, mercuric chloride, and p-aminobenzoic acid completely inactivated the protease. The enzyme had no requirement for calcium. The sites of cleavage of the oxidized B-chain of insulin were the Cys-Gly and Arg-Gly bonds. The enzyme was therefore an endopeptidase. Cleavage of Na-benzoyl-L-arginine ethyl ester, but not Na-benzoyl-L-tyrosine ethyl ester, suggests that the protease is of the trypsin family. On the basis of its physical and enzymic properties the protease is a serine proteinase and, consistent with existing terminology, has been named proteinase pemB.
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PMID:Purification and properties of a protease from developing porcine dental enamel. 268 9

The germinal center of lymphoid tissues is a critical microenvironmental site of B cell activation and differentiation in response to antigenic stimuli. However, characterization of germinal center cells (GCC) in tissue sections has proved technically difficult. Therefore, we have employed two-color flow cytometric analysis of suspended human tonsillar lymphocytes in order to define more precisely the immunologic features of GCC. These cells were identified in suspension by virtue of their specific surface binding of the lectin peanut agglutinin (PNA), confirmed by tissue immunoperoxidase studies. Phycoerythrin-labeled lectin was used in combination with a variety of fluorescein-labeled antibodies in order to identify subpopulations of tonsillar lymphocytes. The majority of PNA+ cells were B cells, and both PNA+ and PNA- B cells stained for surface immunoglobulin light chains. PNA+ cells lacked surface IgD, but included cells with surface IgG and IgM. Both PNA+ and PNA- cells stained for B1, B2, BA-1, Leu-12, Leu-14, CR-I, and HLA-DR antigens, whereas CALLA was present only on PNA+ cells. There were differences between PNA+ and PNA- cells in the relative expression of B1 and B2 antigens, possibly reflecting differences in B cell activation or maturation. A small proportion of T cells were PNA+, including both helper/inducer and suppressor/cytotoxic phenotypes. PNA+ cells included both small and large lymphoid cells, and almost all DNA synthetic activity was associated with the large PNA+ cells. PNA+ B cells isolated by cell sorting had morphologic features characteristic of GCC. Therefore, PNA+ cells in suspension appeared to represent GCC, and features of these cells that cannot be convincingly shown in tissue section studies were demonstrated by flow cytometry.
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PMID:The human lymph node germinal center cell: characterization and isolation by using two-color flow cytometry. 294 95


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