Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of the meningococcal transferrin receptor, detected by assay with human transferrin conjugated to peroxidase, was regulated by the level of iron in the medium. The transferrin receptor was identified by SDS-PAGE and Western blot analysis, as a 71,000 molecular weight iron-regulated outer membrane protein in Neisseria meningitidis B16B6. Growth studies with iron-deficient cells and competition binding experiments demonstrated that the meningococcal receptor was species-specific for human transferrin. Reciprocal competitive binding experiments and limited proteolysis of intact cells indicated that the transferrin and lactoferrin receptors are distinct.
 ...
PMID:Identification and characterization of the transferrin receptor from Neisseria meningitidis. 313 85

Two approaches were used to identify and characterize the presence of tissue plasminogen activator (t-PA) in megakaryocytes and platelets. We investigated the fibrinolytic activity of human megakaryocytes (MK) and platelets. The presence of t-PA antigen in megakaryocytes and platelets was demonstrated using immunocytochemical techniques and polyclonal or monoclonal antibodies specific for t-PA. When cells were applied to fibrin plates, lysis zones developed around isolated human megakaryocytes, whereas no fibrinolytic activity appeared when either intact washed platelets or platelet lysate were deposited. After SDS-PAGE of platelet and MK extracts (Triton X-100) immunoblotting and peroxidase staining identified t-PA antigen in several bands. Zymographic analysis of SDS-PAGE carried out on fibrin film overlays identified one or two zones corresponding to free or complexed t-PA. These results indicate that t-PA is present in platelets as well as in the precursor cells, however, in platelets, t-PA may not be immediately available for plasminogen activation and fibrin degradation. From our findings and from previous work of others, it appears that platelets may either activate or inhibit the fibrinolytic system. Therefore the conditions of plasminogen activation by platelet t-PA and plasmin inhibition by platelet alpha 2-antiplasmin or other inhibitors have to be precised before the role of platelets in clot dissolution is understood. The physiological role of platelets in fibrinolysis and clot dissolution remains unclear. In 1953, the antifibrinolytic activity of blood platelets was demonstrated and in the early 1960's a fibrinolytic activity, increasing with platelet concentration in the experimental system, was shown.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Tissue plasminogen activator in human megakaryocytes and platelets: immunocytochemical localization, immunoblotting and zymographic analysis. 314 87

Immobilized D-galactose-specific lectin from Zea mais was used to purify rat brain membrane glycoproteins. The membrane glycoproteins preliminarily washed from soluble proteins were solubilized consecutively by 2% triton X-100 and 1% SDS. PAG-electrophoresis with SDS and 2-mercaptoethanol revealed 10 polypeptide bands (Mm 109, 62, 59, 54, 51, 42, 16, 14, 12.5 and 12 kDa) in the membrane fraction of glycoproteins solubilized with triton X-100. Additional solubilization with SDS revealed 3 bands (Mm 109, 62, and 54 kDa). Only 3 polypeptide bands (Mm 62, 59, 42 kDa) were identified when analogous procedure was used for purification of the rat liver glycoproteins. Horse radish peroxidase labelled D-galactose-specific lectin from Zea mais was found to bind to neuron bodies and neurites in the cerebellum. It is suggested that the identified brain-specific membrane glycoproteins may take part in the cell adhesion between neurons.
 ...
PMID:[A study of membrane glycoproteins from the rat brain using D-galactose-specific lectin]. 323 4

Earlier studies have localized the Heymann nephritis (HN) autoantigen (gp330) in the coated pits of the plasma membrane and multivesicular bodies of the glomerular epithelial cell. Because of these locations in the glomerular epithelial cells, it has been suggested that the HN Ag may be a receptor. The aim of our study was to search for a ligand which can bind the HN autoantigen. Normal rat serum was subjected to SDS-PAGE under reducing and non-reducing conditions followed by Western analysis of the separated polypeptides. A reaction was revealed directly by autoradiography using 125I labeled HN autoantigen as a probe and indirectly by enzyme immunodetection using unlabeled nephritogenic autoantibody (anti-gp330) eluted from glomeruli of diseased rats followed by biotinylated rabbit anti-rat IgG avidin-peroxidase complex. A polypeptide of 76 kDa Mr was identified under non-reducing conditions as a serum protein reacting with the HN autoantigen. Reactivity of the 76-kDa polypeptide was lost when serum was electrophoresed under reducing conditions. Direct binding of the 76-kDa polypeptide obtained from serum to the HN autoantigen obtained from kidney suggests that the 76-kDa polypeptide may be a ligand for the autoantigen. This is the first documentation of a possible ligand for the HN autoantigen. Not only does this polypeptide bind to the HN autoantigen but it also shows direct binding with the nephritogenic autoantibody eluted from glomerular deposits. This characteristic of the 76-kDa polypeptide indicates that this serum protein may potentially play a role in the development of the glomerular lesion of active HN. Further analysis of this serum component should assist in understanding the normal function of the HN autoantigen.
 ...
PMID:A possible ligand of serum origin for the kidney autoantigen of Heymann nephritis. 326 6

The most abundant protein in fluid from the mouse cauda epididymidis, designated CP 27, is a glycoprotein that migrates at approximately 27000 daltons on SDS-polyacrylamide gels. Samples of CP 27 were isolated by preparative gel electrophoresis and were used to raise a guinea-pig polyclonal antiserum, which reacted with a single band on western blots of caudal epididymal fluid. This antiserum was used for immunocytochemical localization of CP 27 in histological sections of mouse epididymis using the peroxidase-antiperoxidase and protein A-gold methods. The most proximal staining with anti-CP 27 was in segment 6 of the distal caput epididymidis, where the lumen and a portion of the supranuclear cytoplasm of principal cells were stained. In contrast, in the distal corpus and cauda epididymidis (segments 8-11), there was pronounced staining of the luminal contents, sterocilia, and scattered cells identified as the "light" cells of the epididymal epithelium. Although CP 27 was found in the epididymal lumen of all segments distal to segment 6, the intensity of staining appeared to decline distally in the cauda epididymidis. Control sections exposed to pre-immune serum instead of anti-CP 27 showed no reaction. The results suggest that CP 27, the major glycoprotein of cauda epididymal fluid, is synthesized by principal cells of segment 6 of the distal caput epididymidis. CP 27 may be among the substances absorbed from the lumen by the light cells of the distal epididymis.
 ...
PMID:Immunocytochemical localization of the major glycoprotein of epididymal fluid from the cauda in the epithelium of the mouse epididymis. 328 51

Monoclonal antibodies of IgG1 type immunoglobulin, directed against soluble CML antigen isolated from the reactive CML peripheral myelocytes, were reported. These MAbs were further investigated for their reactivity by 125I-Protein-A binding assays, indirect immunofluorescence tests, cytotoxicity, SDS-PAGE, immunoelectrophoresis, and by immunodiffusion suggesting that they recognized antigens specific mostly to undifferentiated cells. These were tested against various leukemic peripheral blood leukocytes, bone marrow cells, established cell lines of various origin, and with many solid tumor cells and demonstrated specific reactivity with CML myelocytes alone and cell lines of myeloid origin. Indirect immunoperoxidase staining of single cell preparation revealed peroxidase localization in most promyelocytes and in few mature myelocytes from CML PBL/BM cells, thus helping in identifying the exact type (morphology) involved in reacting specifically with these MAbs.
 ...
PMID:Unique monoclonal antibodies against soluble membrane proteins of human CML myelocytes reactive with human myeloid progenitor cells. 328 83

CellCAM 105 is an integral membrane glycoprotein, with apparent Mr 105,000, which has been purified from rat liver plasma membranes. It consists of two structurally similar, highly glycosylated polypeptide chains and is involved in cell-cell adhesion of adult rat hepatocytes in vitro. In this communication we report on the distribution and cell surface location of cellCAM 105 in rat tissues, obtained by using highly sensitive immunodetection systems based on complex formation between biotinylated antibodies, biotinylated peroxidase and avidin, or on antibodies coupled to alkaline phosphatase. CellCAM was found in many organs and organ systems, including liver, kidney, blood, blood vessels, glands, respiratory system, and gastrointestinal tract. It was mainly localized to epithelial structures but showed a varying cell surface distribution. In some cell types it was predominantly localized to cell-cell contact areas. In other cell types the highest concentrations were seen in brush-border areas containing densely packed microvilli. In addition to epithelial structures, cellCAM 105 was found in rat platelets, where it became strongly expressed on the cell surfaces after activation with ADP or collagen, suggesting that it might be involved in platelet adhesion and/or aggregation mechanisms. Granulocytes also contained cellCAM 105. By SDS-PAGE/immunoblotting, significant differences were found in the apparent Mr values of cellCAM 105 in different tissues. The collected data suggest that cellCAM 105 participates in several different cell surface membrane interactions, of which the common denominator might be membrane-membrane binding.
 ...
PMID:Immunohistochemical localization of cellCAM 105 in rat tissues: appearance in epithelia, platelets, and granulocytes. 329 Mar 31

Human salivary peroxidase (SPO) has been purified to homogeneity by subjecting human parotid saliva to immunoaffinity, cation exchange, and affinity chromatography. These procedures resulted in a 992-fold purification of the enzyme. When purified SPO was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), three Coomassie stainable bands were apparent, all of which stained positive for enzyme activity. The apparent molecular weights of the three bands were 78,000, 80,000, and 280,000 as analyzed by SDS-PAGE. Reduction with 2-mercaptoethanol resulted in a decreased mobility of these bands, and enzyme activity could no longer be detected on the gels. The SPO preparation had the characteristic peroxidase heme spectrum in the range 405-420 nm. The ratio between the absorbance of the Soret band (412 nm) and the absorbance at 280 nm was 0.81. The enzyme activity was inhibited by the classical peroxidase inhibitors cyanide and azide. Salivary peroxidase is similar to bovine lactoperoxidase (LPO) in amino acid composition, in ultraviolet and visible spectrum, in reaction with cyanide, in susceptibility to 2-mercaptoethanol inactivation, and in thermal stability. The two enzymes differ in carbohydrate composition and content. SPO contains 4.6% and LPO 7% total neutral sugars. The ratio of glucosamine to galactosamine is 2:1 in SPO and 3:1 in LPO. SPO contains mannose, fucose, and galactose in a molar ratio of 1.5:1.5:1.0, while the ratio was 14.9:0.5:1.0 in LPO. Glucose was present in both preparations in minor amounts. The concentration of azide required for 50% inhibition of enzyme activity was 20-fold greater for LPO than for SPO.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Purification and characterization of human salivary peroxidase. 334 28

Four monoclonal antibodies generated against rat, hepatocyte lysosomal integral membrane protein (LIMPs) (Barriocanal et al., 1986a, b) were used as probes to ascertain the distribution of similar proteins in normal rat kidney (NRK) cells. Comparison of immunoprecipitations of LIMPs 1-4 from hepatocytes and NRK cells revealed a marked similarity in the proteins, in both cell types, as determined by SDS-PAGE. Further, the LIMP epitopes recognized by the antibodies are situated intravesicularly. Ultrastructural immunocytochemistry, using pre-embedding peroxidase, revealed that primary and secondary lysosomes in NRK cells are readily stained with all four antibodies, as well as vesicles in the Golgi region. Immunofluorescence microscopy of non-permeabilized NRK cells with antibodies recognizing LIMPs 1 and 4 illustrated a limited but significant punctate staining pattern of the cell surface. Ultrastructural immunoperoxidase indicated these sites to be cell surface localized coated pits and vesicles. However, it is known that all LIMPs are expressed on the cell surface, albeit at different concentrations, although the total number of each LIMP per cell, respectively, is approximately the same (Barriocanal et al., 1987). Treatment of NRK cells with the acidotropic agent NH4Cl decreased the cell surface expression of LIMPs 1, 3 and 4, but had no effect on LIMP 2. Further, the relative diminution of the cell surface expression varied among the four LIMPs. These results are interpreted to suggest that not all lysosomes contain the same integral membrane proteins in their vesicle container.
 ...
PMID:Differential cell surface expression of four lysosomal integral membrane proteins (LIMPs) in normal rat kidney cells. 338 13

A high-resolution technique has been used to study differentiation-related and leukemia-associated glycoproteins. Cells are labeled with the membrane-impermeable probe sulfo-N-hydroxysuccinimidyl-biotin. Nonionic detergent extracts are subjected to affinity chromatography on a number of immobilized lectins and after polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE) and western transfer, the biotin-labeled glycoproteins are visualized by using avidin-horseradish peroxidase and 4-chloronaphthol. With the aid of the lectins concanavalin A, Dolichos biflouros agglutinin, Lens culinaris hemagglutinin, peanut agglutinin, pokeweed mitogen, Ricinus communus agglutinin I, soybean agglutinin, Ulex europeus agglutinin I (UEA), and wheat germ agglutinin, each purifies different glycoprotein subsets from the same cell type. Mature cells of distinct hematopoietic lineages differ considerably in their cell surface glycoprotein patterns. This technique was used to analyze the glycoproteins of human leukemia cells before and after the induction of differentiation. K562 cells differentiated along different lineages after treatment with phorbol 12-myristate 13-acetate, sodium butyrate, dimethyl sulfoxide, or hemin. Limited specific alterations were observed with a number of lectins when K562 erythroleukemia cells were induced to differentiate. Among these, a number of bands were identified that were either lost or appeared after induction of differentiation with all four agents. In contrast, the glycoproteins bound by UEA were drastically diminished after induction of differentiation, and the remaining UEA-bound glycoproteins bore little resemblance to those of the cells before treatment. This high-resolution technique may be useful as a general method for the examination of cell surface glycoprotein differences. Once specific glycoprotein alterations are detected, lectin affinity chromatography and SDS-PAGE allow purification of antigens for the production of monoclonal antibodies.
 ...
PMID:Analysis of cell surface glycoprotein changes related to hematopoietic differentiation. 339 8


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>