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Gene Review

Lpo  -  lactoperoxidase

Mus musculus

Synonyms: 5830499B15Rik
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Disease relevance of Lpo


High impact information on Lpo

  • This suggested that cytotoxicity was not dependent upon myeloperoxidase, and that lactoperoxidase may have diverted H2O2 from the oxidation of target cells to oxidation of substances in serum [6].
  • Neither azide nor cyanide reduced cytolysis, but there was marked inhibition by lactoperoxidase and iodide [6].
  • Examination of the labeled molecules precipitated from detergent extracts of spleen cells and thymocytes iodinated by the lactoperoxidase technique by SDS-PAGE confirm that there are structural differences between the antigens found on B and T lymphocytes [7].
  • Specific anti-Ly sera were employed to precipitate Ly antigens from Nonidet P-40 extracts of mouse thymocytes labeled with 125I using lactoperoxidase and with NaB3H4 using galactose oxidase [8].
  • Lymphoid cells from strain 2 and strain 13 guinea pigs were surface labeled with 125I by the lactoperoxidase technique [9].

Chemical compound and disease context of Lpo


Biological context of Lpo

  • We describe a method for the specific radioiodination of pinocytic vesicles (PVs) based upon the simultaneous endocytosis of lactoperoxidase (LPO) and glucose oxidase (GO) [13].
  • Iodination of cells in suspension results in lactoperoxidase-specific iodide incorporation with no loss of cell viability under the conditions employed, less than 3% lipid labeling, and more than 90% of the labeled species identifiable as monoiodotyrosine [14].
  • Initial experiments indicated that LPO was interiorized by the macrophage cell line J774 by fluid phase pinocytosis and without detectable binding to the plasma membrane (PM) [13].
  • This molecule was a major surface constituent of myeloid cells with 10(6) antibody binding sites per cell containing 10% of total 125I incorporated by the lactoperoxidase procedure [15].
  • These results indicate that upon binding fatty acid, 422(aP2) protein undergoes a conformational change whereby Tyr19, which lies within a consensus-type sequence for tyrosine kinase substrates, becomes accessible for phosphorylation by the insulin receptor tyrosine kinase and to iodination by lactoperoxidase [16].

Anatomical context of Lpo

  • It is possible that the marked degree of exposure of the 50,000 mol wt polypeptide to immobilized LPO is related to the unique strength of macrophages attachment [17].
  • These organelles rapidly fuse with preexisting lysosomes and are converted to phagolysosomes (PL) that demonstrates both acid phosphatase and lactoperoxidase activities [18].
  • LPO was iodinated only after PV labeling and was present within organelles demonstrating latency [13].
  • The 55,000 mol wt polypeptide can also be identified in Triton X-100 cytoskeletons from L929 cells after labeling with soluble LPO either before or after detergent lysis [17].
  • The gel patterns of iodinated proteins showed specific differences in the availability of membrane proteins to lactoperoxidase labeling between inside-out and right-side-out membranes [19].

Associations of Lpo with chemical compounds

  • After labeling of both L929 cells and macrophages with immobilized LPO, all polypeptides in this molecular weight region were subjected to peptide mapping by simultaneous limited proteolysis and electrophoresis in a second SDS polyacrylamide slab gel [17].
  • Use of immobilized lactoperoxidase to label L cell proteins involved in adhesion to polystyrene [20].
  • Lactoperoxidase beads were used to selectively label the apical surfaces of confluent endothelial monolayers, the total surfaces of nonenzymatically resuspended cells, and the basal surfaces of monolayers inverted on poly-L-lysine-coated coverslips, while maintaining greater than 98% viability in all samples [21].
  • Platelet LFA-1, as demonstrated by surface iodination with lactoperoxidase and by labeling sialic acid residues with sodium borohydride, was not a major component of the platelet membrane [22].
  • Similarly, tunicamycin prevents the appearance of membrane-associated viral antigens that can be labeled externally by lactoperoxidase-mediated iodination and it protects the cells against the cytolytic effects of MTV-specific antiserum and complement [23].

Other interactions of Lpo

  • Experiments with specific antisera show that TSP-180 is not lactoperoxidase, fetal bovine serum protein, large external transformation-sensitive protein, or an antigen related to murine leukemia virus proteins [24].
  • These proteins were also radiolabeled by lactoperoxidase catalyzed iodination and were sensitive to mild tryptic digestion, suggesting that they localized on the cell surface or in the extracellular matrix [25].
  • The superpotent and enzymatically resistant alpha MSH analog, Nle4,D-Phe7-alpha MSH (NDP-MSH), was radioiodinated using lactoperoxidase (Enzymobeads) and purified by reverse phase chromatography for use as a tracer [26].
  • Iodination by fungi with lactoperoxidase was reduced when blastoconidia were incubated at 25 degrees C or in the presence of catalase and the metabolic inhibitors rotenone, antimycin A, and 2-deoxyglucose [27].
  • Lactoperoxidase iodination of cell surface proteins showed the appearance of an Mr 86,000 protein in the tumorigenic and metastatic cell variants [28].

Analytical, diagnostic and therapeutic context of Lpo


  1. Release of surface macromolecules by human melanoma and normal cells. Bystryn, J.C., Tedholm, C.A., Heaney-Kieras, J. Cancer Res. (1981) [Pubmed]
  2. Immunotoxins containing glucose oxidase and lactoperoxidase with tumoricidal properties: in vitro killing effectiveness in a mouse plasmacytoma cell model. Stanislawski, M., Rousseau, V., Goavec, M., Ito, H. Cancer Res. (1989) [Pubmed]
  3. Heterogeneity of a labeled tumor surface protein from a murine lung carcinoma demonstrated by two-dimensional electrophoresis. Eisinger, R.W., Kennel, S.J. Cancer Res. (1981) [Pubmed]
  4. The effects of processing inhibitors of N-linked oligosaccharides on the intracellular migration of glycoprotein E2 of mouse hepatitis virus and the maturation of coronavirus particles. Repp, R., Tamura, T., Boschek, C.B., Wege, H., Schwarz, R.T., Niemann, H. J. Biol. Chem. (1985) [Pubmed]
  5. Detection of a cell surface antigen found on rat peripheral nervous system neurons and multiple glia: astrocytes, oligodendrocytes, and Schwann cells. Akeson, R., Warren, S.L. J. Neurosci. Res. (1984) [Pubmed]
  6. Extracellular cytolysis by activated macrophages and granulocytes. II. Hydrogen peroxide as a mediator of cytotoxicity. Nathan, C.F., Silverstein, S.C., Brukner, L.H., Cohn, Z.A. J. Exp. Med. (1979) [Pubmed]
  7. Interspecies spleen-myeloma hybrid producing monoclonal antibodies against mouse lymphocyte surface glycoprotein, T200. Trowbridge, I.S. J. Exp. Med. (1978) [Pubmed]
  8. The Ly-3 antigens on mouse thymocytes: immune precipitation and molecular weight characterization. Durda, P.J., Gottlieb, P.D. J. Exp. Med. (1976) [Pubmed]
  9. Guinea pig immune response-related histocompatibility antigens. Partial characterization and distribution. Findelman, F.D., Shevach, E.M., Vitetta, E.S., Green, I., Paul, W.E. J. Exp. Med. (1975) [Pubmed]
  10. Asymmetrical surface IgG on MOPC-21 plasmacytoma cells contains membrane heavy chain and one secretory heavy chain. Goding, J.W. J. Immunol. (1982) [Pubmed]
  11. Cytolysis of B-16 melanoma tumor cells mediated by the myeloperoxidase and lactoperoxidase systems. Odajima, T., Onishi, M., Hayama, E., Motoji, N., Momose, Y., Shigematsu, A. Biol. Chem. (1996) [Pubmed]
  12. A comparison of surface proteins in embryonal carcinoma cells and their differentiated derivatives. Keil-Dlouha, V., Paulin, D., Bagilet, L.K., Keil, B. Biochim. Biophys. Acta (1980) [Pubmed]
  13. Selective iodination and polypeptide composition of pinocytic vesicles. Mellman, I.S., Steinman, R.M., Unkeless, J.C., Cohn, Z.A. J. Cell Biol. (1980) [Pubmed]
  14. Externally disposed plasma membrane proteins. I. Enzymatic iodination of mouse L cells. Hubbard, A.L., Cohn, Z.A. J. Cell Biol. (1975) [Pubmed]
  15. Murine cell surface glycoproteins. Purification of the polymorphic Pgp-1 antigen and analysis of its expression on macrophages and other myeloid cells. Hughes, E.N., Colombatti, A., August, J.T. J. Biol. Chem. (1983) [Pubmed]
  16. Insulin receptor tyrosine kinase-catalyzed phosphorylation of 422(aP2) protein. Substrate activation by long-chain fatty acid. Hresko, R.C., Hoffman, R.D., Flores-Riveros, J.R., Lane, M.D. J. Biol. Chem. (1990) [Pubmed]
  17. Identification of cytoskeletal components involved in attachment of L929 cells and macrophages to polystyrene. Lanks, K.W., Chin, N.W. J. Cell Biol. (1981) [Pubmed]
  18. The membrane proteins of the vacuolar system I. Analysis of a novel method of intralysosomal iodination. Muller, W.A., Steinman, R.M., Cohn, Z.A. J. Cell Biol. (1980) [Pubmed]
  19. Asymmetric distribution of plasma membrane proteins in mouse L-929 cells. Evans, R.M., Ward, D.C., Fink, L.M. Proc. Natl. Acad. Sci. U.S.A. (1979) [Pubmed]
  20. Use of immobilized lactoperoxidase to label L cell proteins involved in adhesion to polystyrene. Chin, N.W., Lanks, K.W. J. Cell Biol. (1980) [Pubmed]
  21. Plasmalemmal proteins of cultured vascular endothelial cells exhibit apical-basal polarity: analysis by surface-selective iodination. Muller, W.A., Gimbrone, M.A. J. Cell Biol. (1986) [Pubmed]
  22. Expression of the leukocyte functional molecule (LFA-1) on mouse platelets. McCaffery, P.J., Berridge, M.V. Blood (1986) [Pubmed]
  23. The role of protein glycosylation in the compartmentalization and processing of mouse mammary tumor virus glycoproteins in mouse mammary tumor virus-infected rat hepatoma cells. Firestone, G.L. J. Biol. Chem. (1983) [Pubmed]
  24. Characterization of a tumor cell surface protein with heterologous antisera to a spontaneous BALB/c lung carcinoma. Kennel, S.J. Cancer Res. (1979) [Pubmed]
  25. Fibronectin phosphorylation by ecto-protein kinase. Imada, S., Sugiyama, Y., Imada, M. Exp. Cell Res. (1988) [Pubmed]
  26. Specific receptors for alpha-melanocyte-stimulating hormone are widely distributed in tissues of rodents. Tatro, J.B., Reichlin, S. Endocrinology (1987) [Pubmed]
  27. Generation of hydrogen peroxide by Candida albicans and influence on murine polymorphonuclear leukocyte activity. Danley, D.L., Hilger, A.E., Winkel, C.A. Infect. Immun. (1983) [Pubmed]
  28. The establishment and characterization of a new BALB/c angiosarcoma tumor system. Zvibel, I., Raz, A. Int. J. Cancer (1985) [Pubmed]
  29. Immunoprecipitation and partial characterization of diphtheria toxin-binding glycoproteins from surface of guinea pig cells. Proia, R.L., Hart, D.A., Holmes, R.K., Holmes, K.V., Eidels, L. Proc. Natl. Acad. Sci. U.S.A. (1979) [Pubmed]
  30. Differential expression of cell surface glycoproteins on various organ-derived microvascular endothelia and endothelial cell cultures. Belloni, P.N., Nicolson, G.L. J. Cell. Physiol. (1988) [Pubmed]
  31. Tissue-culture cell fractionation. Fractionation of cellular membranes from 125I/lactoperoxidase-labelled Lettrée cells homogenized by bicarbonate-induced lysis: resolution of membranes by zonal centrifugation and in sucrose and metrizamide gradients. Graham, J.M., Coffey, K.H. Biochem. J. (1979) [Pubmed]
  32. Pathways of endocytosis in cultured macrophages. Electron microscopic autoradiographic tracing of iodinated plasma membrane proteins. Stenseth, K., Thyberg, J. Eur. J. Cell Biol. (1986) [Pubmed]
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