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  • The polypeptide composition of moving and stationary neurofilaments in cultured sympathetic neurons. 17285620

    Studies on the axonal transport of neurofilament proteins in cultured neurons have shown they move at fast rates, but their overall rate of movement is slow because they spend most of their time not moving. Using correlative light and electron microscopy, we have shown that these proteins move in the form of assembled neurofilament polymers. However, the polypeptide composition of these moving polymers is not known. To address this, we visualized neurofilaments in cultured neonatal mouse sympathetic neurons using GFP-tagged neurofilament protein M and performed time-lapse fluorescence microscopy of naturally occurring gaps in the axonal neurofilament array. When neurofilaments entered the gaps, we stopped them in their tracks using a rapid perfusion and permeabilization technique and then processed them for immunofluorescence microscopy. To compare moving neurofilaments to the total neurofilament population, most of which are stationary at any point in time, we also performed immunofluorescence microscopy on neurofilaments in detergent-splayed axonal cytoskeletons. All neurofilaments, both moving and stationary, contained NFL, NFM, peripherin and alpha-internexin along>85% of their length. NFH was absent due to low expression levels in these neonatal neurons. These data indicate that peripherin and alpha-internexin are integral and abundant components of neurofilament polymers in these neurons and that both moving and stationary neurofilaments in these neurons are complex heteropolymers of at least four different neuronal intermediate filament proteins.
    Document Type:
    Reference
    Product Catalog Number:
    AB1989
    Product Catalog Name:
    Anti-Neurofilament H (200 kDa) Antibody, CT

  • The polypeptide encoded by the cDNA for human cell surface antigen Fas can mediate apoptosis. 1713127

    Mouse anti-Fas monoclonal antibody has a cytolytic activity on human cells that express the antigen. Complementary DNAs encoding the cell surface antigen Fas were isolated from a cDNA library of human T cell lymphoma KT-3 cells. The nucleotide sequence of the cDNAs revealed that the molecule coding for the Fas antigen determinant is a 319 amino acid polypeptide (Mr 36,000) with a single transmembrane domain. The extracellular domain is rich in cysteine residue, and shows a similarity to that of human tumor necrosis factor receptors, human nerve growth factor receptor, and human B cell antigen CD40. Murine WR19L cells or L929 cells transformed with the human Fas antigen cDNA were killed by the anti-Fas antibody in the process known as apoptosis.
    Document Type:
    Reference
    Product Catalog Number:
    05-201
    Product Catalog Name:
    Anti-Fas Antibody (human, activating), clone CH11

  • The major polypeptide of scrapie-associated fibrils (SAF) has the same size, charge distribution and N-terminal protein sequence as predicted for the normal brain protein ... 3096712

    Scrapie-associated fibrils (SAF) are unique structures characteristic of the group of unconventional slow infections which includes scrapie and Creutzfeldt-Jakob disease. A major component of hamster fibrils has been described as a protease-resistant glycoprotein with an apparent mol. wt of 27,000-30,000 (PrP27-30). However, we report here that if fibrils are prepared by procedures designed to minimise proteolysis the PrP proteins co-purifying with hamster SAF have mol. wts of 33,000-35,000 (PrP33-35) and 26,000-29,000 (PrP26-29). We find a Lys-Lys-Arg-Pro-Lys sequence at the amino terminus of these SAF proteins, that is absent from PrP27-30, and which has recently been predicted to be the N-terminal sequence of the native PrP protein of uninfected brain. The major SAF protein (PrP33-35) and its normal brain homologue are shown to have the same apparent mol. wt and ionic charge distribution by two-dimensional gel analysis, silver staining and immunoblotting. These results support our view that PrP33-35 and the normal brain PrP protein may have the same covalent structure, and that the PrP protein is recruited into these amyloid-like SAF or into association with a non-protein component of SAF by an irreversible event initiated directly or indirectly by scrapie infection.
    Document Type:
    Reference
    Product Catalog Number:
    AG210
    Product Catalog Name:
    Prion Protein, recombinant

  • VLA-3: a novel polypeptide association within the VLA molecular complex: cell distribution and biochemical characterization. 2430809

    The family of human T cell activation-associated proteins, named VLA complex, is formed by the molecular association of cell surface glycoproteins of 210, 165, 130 and 80 kDa. In this report, we describe eight different monoclonal antibodies (HP mAb) specific for the 80-kDa polypeptide which preferentially associates with the 165-kDa member. Comparative immunoprecipitation and cell-binding studies demonstrated that the HP mAb recognize an epitope(s) on the 165/80 kDa subset different from those recognized by other anti-VLA mAb previously described. Furthermore, cellular and tissue distribution studies by flow cytometry and peroxidase staining showed that the HP reactivity pattern is different from other VLA specificities. The 165/80-kDa complex defined by HP mAb is present on human thymocytes, peripheral blood lymphocytes as well as on T, B and myelomonocytic cell lines. However, only the 80-kDa subunit was precipitated by HP mAb from activated T lymphocytes. These results suggest that the association between the 165- and 80-kDa subunits diminishes during the activation process, and that the epitopes recognized by the HP mAb are located on the 80-kDa protein. The novel polypeptide association of 165/80 kDa has been termed VLA-3.
    Document Type:
    Reference
    Product Catalog Number:
    MAB1383
    Product Catalog Name:
    Anti-Integrin α4 Antibody, clone HP2/1

  • Polypeptide growth factors: roles in normal and abnormal cell growth. 3318882

    An increasing number of polypeptide growth factors have been identified that regulate not only cell proliferation but an extraordinary range of cell activities, including matrix protein deposition and resolution, the maintenance of cell viability, cell differentiation, inflammation, and tissue repair. Normal cells appear to require growth factors for proliferation and for maintenance of viability. Cells that secrete a polypeptide growth factor have an advantage in growth. These factors can act either externally through cell surface receptors or perhaps internally during the transport of receptors and growth factors through the ER and Golgi, causing autocrine stimulation of cell growth. Depending on the cell type, growth factors can also be potent inhibitors of cell growth rather than stimulating growth, and the effects can depend on the presence or absence of other growth factors. Platelet-derived growth factor has been shown to be nearly identical to the product of the v-sis gene of the simian sarcoma virus, which appears to cause cell transformation through its interactions with the PDGF receptor activating the tyrosine kinase activity of the PDGF receptor. Similarly, two proto-oncogenes, c-erbB and c-fms, encode growth factor receptors. The EGF receptor activity of the v-erb oncogene product appears to be constitutively activated without the need for growth factor, perhaps because of the truncation at the amino terminus deleting the EGF binding domain. The induction of the myc and the fos proteins by growth factor stimulation of quiescent cells, as well as the potential for the p21 product of the ras oncogene to act as an intermediate in transducing adrenergic signals, provide direct evidence that these pathways are important for stimulation of cell growth. Cells transformed by the v-sis oncogene always appear to bear PDGF cell surface receptors, which suggests that this oncogene has a specific requirement of the PDGF receptor for transformation. In contrast, cells transformed by the v-erbB and v-fms oncogenes are not stimulated by EGF or by CSF-1. Thus it seems likely that the tyrosine kinase activity of the corresponding receptor is ubiquitously expressed in these cases. Major questions remain unanswered. In particular, what are the mechanisms by which growth factors initiate pathways leading to DNA synthesis? What are the physiological substrates of the growth factor receptor tyrosine kinase? Considerable effort also is needed to further define the cellular specificity of the different growth factors, particularly within intact tissues, and to determine how the various growth factors interact.(ABSTRACT TRUNCATED AT 400 WORDS)
    Document Type:
    Reference
    Product Catalog Number:
    06-127
    Product Catalog Name:
    Anti-PDGF Antibody, neutralizing

  • Pancreatic polypeptide - a postulated new hormone: identification of its cellular storage site by light and electron microscopic immunocytochemistry. 782992

    A peptide, referred to as pancreatic polypeptide (PP), has recently been isolated from the pancreas of chicken and of several mammals. PP is thought to be a pancreatic hormone. By the use of specific antisera we have demonstrated PP immunoreactivity in the pancreas of a number of mammals. The immunoreactivity was localized to a population of endocrine cells, distinct from the A, B and D cells. In most species the PP cells occurred in islets as well as in exocrine parenchyma; they often predominated in the pancreatic portion adjacent to the duodenum. In opossum and dog, PP cells were found also in the gastric mucosa. In opossum, the PP cells displayed formaldehyde - induced fluorescence typical of dopamine, whereas no formaldehyde-induced fluorescence was detected in the PP cells of mouse, rat and guinea pig. Also in these latter species, however, PP cells appear to possess amine-handling properties, a feature common to many peptide hormone-producing cells. The ultrastructure of the PP cells was defined by combining immunohistochemistry of semi-thin plastic sections with electron microscopy of adjacent ultrathin sections. PP cells show the ultrastructural features of peptide hormone-secreting cells. The PP cells of cat and dog contain fairly large, rather electron-lucent granules, and are probably identical with the previously described F cells. The PP cells of rat, guinea-pig, chinchilla and man contain small, fairly electron-dense granules. In these latter species no F cells are found. By immunoperoxidase staining of ultrathin sections, the PP immunoreactivity was found to be localized to the cytoplasmic granules. These observations provide support for the view that PP is a true pancreatic hormone.
    Document Type:
    Reference
    Product Catalog Number:
    AB939

  • Identification of polypeptide components of the Epstein-Barr virus early antigen complex with monoclonal antibodies. 6306272

    Three monoclonal antibodies were produced against the Epstein-Barr virus-induced early antigen complex. These antibodies were shown to be specific for the early antigen complex by the fact that they only reacted with cells supporting a permissive or abortive Epstein-Barr virus infection and their synthesis was not affected by inhibitors of viral DNA synthesis. One monoclonal antibody, designated R3, was directed against a diffuse component of the early antigen complex since it reacted by immunofluorescence with cells fixed in acetone or methanol. The other two monoclonal antibodies, designated K8 and K9, reacted with a methanol-sensitive restricted component of this complex. The appearance of the R3 antigen in P3HR-1 superinfected Raji cells occurred approximately 4 h earlier than the antigen detected by K8. By both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and radioimmunoelectrophoresis, it was determined that the R3 monoclonal antibody recognized two major polypeptides with molecular weights of approximately 50,000 to 52,000, whereas K8 and K9 precipitated a protein of approximately 85,000. The R3 monoclonal antibody also immunoprecipitated an in vitro primary translation product. It was, therefore, possible to map this product to the Epstein-Barr virus DNA BamH1 M fragment. These in vitro products were slightly smaller than the in vivo proteins, suggesting that these proteins probably undergo posttranslational modification during the virus replication cycle.
    Document Type:
    Reference
    Product Catalog Number:
    MAB8186
    Product Catalog Name:
    Anti-EBV EA-D-p52/50 Antibody, clone R3

  • Vasoactive intestinal polypeptide: abundant immunoreactivity in neural cell lines and normal nervous tissue. 1273576

    Vasoactive intestinal polypeptide immunoreactivity is present in high concentrations in clonal lines of neuronal and glial origin. The central nervous system and sympathetic ganglia are also rich in the peptide. The findings suggest that this peptide, hitherto thought limited to the gastrointestinal tract, is widely distributed in neural tissue and may have broad physiological significance.
    Document Type:
    Reference
    Product Catalog Number:
    AB982