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)

Acid proteinase activity is associated with the major surface glycoprotein (gp63) of both extracellular promastigotes and intracellular amastigotes of the parasitic protozoan, Leishmania mexicana. The enzyme purified by monoclonal affinity chromatography from promastigotes is strongly inhibited by metal ion chelators, which is reversible by the addition of Zn(II). This proteinase loses its activity after dialysis against 1,10-phenanthroline. The apoenzyme thus prepared is reactivated substantially by Zn(II) and partially by Cu(II), Cd(II), Co(II), or Ni(II). From the recently published structure of the gene encoding gp63, we identify hitherto unrecognized sequences, which can be aligned to the consensus zinc-binding sites of other known metalloproteinases. Anti-gp63 polyclonal antibodies, but not the monoclonals, precipitate similar molecules from amastigotes. These molecules differ slightly from gp63 in electrophoretic mobility but have similar endopeptidase activity. Phagolysosomal degradation by macrophages of proteins entrapped in liposomes is prevented by coating them with native gp63. This protection is lost with heat denaturation of gp63 to kill its enzymatic activity. The proteolytic activity of the metalloenzyme on the surface of these parasites may thus protect their membrane from cytolytic damages during their survival, differentiation, and multiplication in the phagolysosomes of macrophages.
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PMID:Surface acid proteinase (gp63) of Leishmania mexicana. A metalloenzyme capable of protecting liposome-encapsulated proteins from phagolysosomal degradation by macrophages. 270 73

Renal dipeptidase (EC 3.4.13.11) was solubilized from pig kidney microvillar membranes with bacterial phosphatidylinositol-specific phospholipase C and then purified by affinity chromatography on cilastatin-Sepharose. The enzyme was apparently homogeneous on SDS/polyacrylamide-gel electrophoresis with an Mr of 47,000. Immunohistochemical analysis of the distribution of the dipeptidase showed it to be concentrated in the brush-border region of the proximal tubules in close association with endopeptidase-24.11) (EC 3.4.24.11). The purified dipeptidase was shown to contain 1 mol of inositol/mol and to possess the cross-reacting determinant characteristic of the glycosyl-phosphatidylinositol membrane-anchoring domain. The glycoprotein nature of renal dipeptidase was confirmed by chemical and enzymic deglycosylation. These results establish renal dipeptidase as a glycosyl-phosphatidylinositol-anchored ectoenzyme of the microvillar membrane.
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PMID:Ectoenzymes of the kidney microvillar membrane. Affinity purification, characterization and localization of the phospholipase C-solubilized form of renal dipeptidase. 293 Apr 55

The common acute lymphoblastic leukemia antigen (CALLA) is a 100-kd surface glycoprotein that is present on normal and malignant lymphoid cells. It is a useful marker for distinguishing between clinically important types of acute leukemia. Anti-CALLA monoclonal antibodies (MoAb) also react with mature myeloid cells (granulocytes), where they identify an antigen having a similar molecular weight (mol wt). We now report that the antigens detected by anti-CALLA MoAb on human lymphoid and myeloid cells differ in their behavior and chemistry. Surface-labeling studies indicate that the antigen on lymphoid cells has a mol wt of approximately 100 kd v 110 kd for that on granulocytes. When cells are metabolically labeled with 35S-methionine, differences in the mol wt of these antigens are again observed. Unlike the lymphoid antigen, expression of that on purified granulocytes is not modulated by incubation with specific antibody. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of proteolytic digests of the two antigens fails to clarify their chemical relationship. Thus the antigens detected on these two cell types may share an epitope(s) but be chemically distinct, or CALLA may exist in distinct forms and behave differently on lymphoid cells and granulocytes.
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PMID:Anti-CALLA antibodies identify unique antigens on lymphoid cells and granulocytes. 293 4

The reactivity of five monoclonal antibodies J5, OKB-cALLA, Nu-N1, Nu-N2 and VIL-A1 against the common acute lymphoblastic leukaemia (common-ALL) antigen (glycoprotein 100, CD10); was investigated by indirect immunofluorescence in cell suspensions, and by immunoperoxidase in cytocentrifuge slides of ALL, chronic B cell lymphoproliferative disorders, and plasma cell dyscrasias. The five monoclonal antibodies gave similar positive results with both techniques only in samples of ALL. J5 was positive in variable degrees by immunofluorescence in the majority of B cell disorders examined but this was not confirmed by immunoperoxidase. OKB-cALLA reacted in a similar way to J5 in both techniques, although with a lower percentage of cells by immunofluorescence. Nu-N1, Nu-N2, and VIL-A1 were mainly negative when tested by both immunofluorescence and immunoperoxidase in B cell disorders other than ALL and therefore seemed to be more specific for the diagnosis of common-ALL.
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PMID:Different reactivity of monoclonal antibodies against common acute lymphoblastic leukaemia antigen (CD10). 295 63

The specificities of several monoclonal antibodies described by us earlier were determined more exactly: (1) antibodies MEM-31 and MEM-32 are directed against CD8 and CD5 T cell antigens, respectively: (2) MEM-15 and MEM-18 react with the CD14 monocyte antigen; (3) MEM-28 recognizes the CD45 pan-leucocyte antigen. Several new monoclonal antibodies are described: (4) MEM-55 and MEM-58, reactive with subsets of CD45-related molecules; (5) MEM-43, recognizing a broadly expressed 18-kDa glycoprotein; (6) MEM-57, reacting with the CD3 antigen complex: (7) MEM-59 recognizing the CD43 leucocyte antigen; (8) MEM-74, which reacts with an unidentified antigen strongly expressed on several cell lines and many leukaemic cells but absent from most resting leucocytes; (9) MEM-75, directed against transferrin receptor, and (10) MEM-78, recognizing CD10 (CALLA) antigen.
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PMID:Monoclonal antibodies against human leucocyte antigens. II. Antibodies against CD45 (T200), CD3 (T3), CD43, CD10 (CALLA), transferrin receptor (T9), a novel broadly expressed 18-kDa antigen (MEM-43) and a novel antigen of restricted expression (MEM-74). 296 28

We have investigated the specificity of the proteolytic cleavage of the Rous sarcoma virus glycoprotein precursor by introducing two mutations into the putative cleavage region (Arg-Arg-Lys-Arg). We show that neither a deletion of the cleavage sequence nor a glutamic acid for lysine substitution altered intracellular transport or surface expression of the env gene products. However, both the four-amino-acid deletion and the glutamic acid substitution block processing of the env precursor. Susceptibility of the glutamic acid-substituted env precursor to proteases indicated that tertiary protein structure was unaffected. While inhibitor experiments suggested that more than one endopeptidase might be capable of mediating the proteolytic cleavage, the results presented here point to the presence in the Golgi apparatus of a novel endopeptidase, required for retroviral glycoprotein cleavage, that has a high specificity for lysine-containing peptides.
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PMID:Mutations within the proteolytic cleavage site of the Rous sarcoma virus glycoprotein that block processing to gp85 and gp37. 303 86

Monoclonal antibodies (MAb) were produced by immunization of BALB/c mice with cells from a non-T, non-B acute lymphoblastic leukemia (ALL) cell line. Nine distinct antigens (groups I to IX) were defined by these monoclonal antibodies, some of which appear to be associated with specific stages of cellular differentiation. The number of molecules of each MAb reactive with the ALL cell line, measured in a quantitative cellular radioimmunoassay, varied from 0.6 X 10(5) to 11 X 10(5) molecules/cell, indicating that the antigens identified represent major constituents of the cell surface. The biochemical nature of the antigens was examined on the ALL cell line by antibody affinity chromatography and/or immunoprecipitation and SDS-polyacrylamide gel electrophoresis. Groups I through III are composed of previously described antigens: HLA class I, HLA class II molecules, and CALLA, the common ALL antigen. The other MAb define antigens previously undescribed on non-T, non-B ALL cells. Group IV antigen is a polypeptide of apparent m.w. 95,000 distinct from CALLA. It is expressed on some ALL samples and on the vascular endothelial cells of several tissues. Group V antigen is a single polypeptide chain of m.w. 94,000, also distinct from CALLA and expressed by lymphocytes, thymocytes, acute myelogenous leukemia (AML) cells, and ALL cells. Group VI is a molecular complex composed of two noncovalently associated polypeptides of apparent m.w. 125,000 and 87,000 and appears to be restricted to ALL, AML, macrophages, and hematopoietic precursor cells. Group VII is a glycoprotein of apparent m.w. 85,000, which, within the thymus, is primarily restricted to the medullary area. It is also present on AML, bone marrow cells, and mature T and B lymphocytes. Group VIII is a disulfide-linked complex of apparent m.w. greater than 120,000 under nonreducing conditions. It is resolved into three major polypeptides of apparent m.w. 57,000, 47,000, and 41,000 under reducing conditions. This complex is found in greatest amounts on the non-T, non-B ALL cell line but is also present on AML, ALL, and on subpopulations of normal bone marrow and tonsil cells. Group IX antigen is a single polypeptide chain of apparent m.w. 51,000 on the ALL cell line. This antigen is expressed strongly on ALL and AML samples and on normal bone marrow; much lower antigenic density is found on thymus and tonsil cells. The antigens described here with a series of MAb produced in a single fusion represent a unique array of cell surface molecules of non-T, non-B ALL cells.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Identification of several cell surface proteins of non-T, non-B acute lymphoblastic leukemia by using monoclonal antibodies. 315 38

Effective autologous bone marrow transplantation for leukemia and lymphoma is likely to depend upon the selective removal in vitro of malignant cells from normal human bone marrow precursors. Highly specific cytotoxic conjugates formed by coupling ricin A chain to monoclonal antibodies might prove useful for the selective elimination of malignant cells. Consequently, ricin A chain conjugates have been prepared with several different murine monoclonal antibodies and tested for their ability to eliminate clonogenic Burkitt's lymphoma cells from an excess of human bone marrow. The most active reagents included an antibody:A chain conjugate which bound to the nonpolymorphic chain of the la molecule and another which reacted with the mu heavy chain of cell surface immunoglobulin. Conjugates formed with anti-common acute lymphoblastic leukemia antigen, anti-Mr 26,000 glycoprotein, and anti-B1 were much less active on these Burkitt's cells, contrasting with results of complement-dependent tumor cell lysis. Tumor cell kill was partially inhibited by the addition of greater than 2 X 10(6) human bone marrow cells/ml but could be potentiated by increasing the concentration of conjugate or by the addition of 10 mM ammonium chloride. In the presence of ammonium chloride, at least 4 logs of clonogenic tumor cells could be eliminated within 24 h from a 20-fold excess of bone marrow using 10(-7) M ricin A chain linked to one or two different antibodies. Similar treatment of normal human bone marrow temporarily inhibited granulocyte-macrophage colony-forming units (cell) formation but did not compromise establishment of continuous bone marrow cultures. The degree of selective elimination of tumor cells with A chain antibody conjugates was comparable to that achieved with 4-hydroperoxycyclophosphamide or with multiple monoclonal antibodies and complement.
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PMID:Elimination of clonogenic tumor cells from human bone marrow using a combination of monoclonal antibody:ricin A chain conjugates. 351 Jul 20

Endopeptidase-24.11 (EC 3.4.24.11), a widely distributed cell-surface endopeptidase in pig tissues, was purified by immunoaffinity chromatography from its second most abundant source, lymph nodes. The detergent-solubilized enzyme is a glycoprotein with an apparent subunit Mr of 91,000, by electrophoresis in the presence of SDS. This value is intermediate between those observed in preparations from kidney and intestine. The specific activity (125I-labelled insulin B-chain as substrate) was similar to that prepared from other sources. Immuno-peroxidase and immunofluorescent cytochemical methods with either a monoclonal antibody, GK7C2, or an affinity-purified polyclonal antiserum, RP109, were used to establish the distribution and localization of the antigen in lymph nodes. Examination of many nodes confirmed the variability of endopeptidase-24.11 content from node to node. Pig lymph nodes are composed of functionally discrete nodelets and are anatomically inverted, with medulla being located peripheral to the cortex. Endopeptidase-24.11 was present in medulla, paracortex and cortex. The medulla, containing relatively few lymphocytes, stained more intensely than other zones. Lymphocyte-rich areas stained only weakly, but antigen was detectable in the centres of follicles and more strongly in a band surrounding them. The pattern of staining was reticular in appearance in all zones. In primary cell cultures, set up after enzymic disruption of nodes, the immuno-positive cells were found to be adherent to glass or plastic and to exhibit a fibroblastic morphology. Diffuse surface immunofluorescence and brighter intracellular immunofluorescence in granules were observed in these cells in the first few days of culture, but by the fourth day no immuno-positive cells remained and the fibroblasts that grew to confluence were somewhat different in morphology. The cells expressing the endopeptidase-24.11 antigen did not express Ia antigen and were clearly distinct from antigen-presenting dendritic cells. In appearance and properties they belong to the group described as reticular cells.
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PMID:Endopeptidase-24.11 in pig lymph nodes. Purification and immunocytochemical localization in reticular cells. 353 5

Proteolytic cleavage of influenza virus hemagglutinin (HA) glycoprotein into subunits designated HA1 and HA2 is required for penetration of virus into the cell. It is generally assumed that this cleavage is an intracellular function of the host cell. Human adenoid fibroblast (HAF) lines, which support the growth of influenza A virus but release virus with an uncleaved HA, provide a model system that has allowed exploration of mechanisms of cleavage in vivo. Exposure of HAF-grown influenza virus to nasal secretions from children with respiratory tract symptoms induced HA cleavage and rendered virus fully infectious. Characterization of this proteolytic enzyme, present in the extracellular environment of the respiratory tract, suggests that it is a serine endopeptidase.
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PMID:Role of respiratory tract proteases in infectivity of influenza A virus. 354 17


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