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Dive into the research topics where Alain Paraf is active.

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Featured researches published by Alain Paraf.


Biochemical and Biophysical Research Communications | 1974

Use of a concanavalin a polymer to isolate right side-out vesicles of purified plasma membranes from eukariotic cells

Alain Zachowski; Alain Paraf

Abstract We have purified two plasma membrane populations using a Concanavalin A polymer. It was assumed that vesicles retained by the polymer were right side-out, whereas vesicles not retained were inside-out. 5′-nucleotidase and (Na + + K + ) stimulated Mg ++ ATPase activities were at least two fold higher in inside-out than in right side-out vesicles, though recovered total activity was about 80 % for both enzymes together. Moreover, Concanavalin A modified 5′-nucleotidase activity of right side-out vesicles according to the dose used.


Biochimica et Biophysica Acta | 1979

Inhibition of (Na+ + K+)-ATPase by ouabain: Involvement of calcium and membrane proteins

Lionel Lelievre; Alain Zachowski; Danièle Charlemagne; Patrice Laget; Alain Paraf

Treatment of plasma membrane isolated from murine plasmocytoma MOPC 173 with an EDTA-containing buffer resulted in a 300-fold increase in sensitivity of (Na+ + K+)-stimulated Mg2+-ATPase to ouabain. This phenomenon was associated with the solubilization by EDTA of phospholipid free proteins (approx. 30 000-34 000 daltons) from the cytoplasmic face of the plasma membrane and with removal of about 90% of the membrane bound Ca2+. The recovery of the original resistance to ouabain required specifically Ca2+ and was associated with a binding of the solubilized proteins to the membrane.


Biochemical and Biophysical Research Communications | 1971

Contact inhibition--plasma membranes enzymatic activities in cultured cell lines.

L. Lelièvre; B. Prigent; Alain Paraf

Abstract Two phenotypically stabilized lines of plasmocytoma MOPC 173 - one of which (ME 2 ) is contact inhibited; the other (MF 2 ) is not - have different patterns of plasma membrane enzymatic activities. Mg ++ K + Na + dependent ATPase and 5′ nucleotidase activities of ME 2 decrease sharply when cells come into contact.


FEBS Letters | 1975

Non specific effector‐induced enzyme modulation in isolated plasma membranes

Alain Zachowski; Danièle Migliore-Samour; Alain Paraf; Pierre Jollès

Jussieu 75005 Paris, i+ance ** Laboratoire des ProtPines, Universiti de Paris V, 45, Rue des Saints P&es, 75006 Paris, France *** On leave from Institut National de la Recherche Agronomique, Station de Virologie et d’lmmunologie, 78850 Thiverval-Grignon, France Received 7 January 1975


Cellular and Molecular Life Sciences | 1992

Common antigenic properties of a g-type (goose) and a c-type (duck) egg white lysozyme: Antibody responses in rabbits and mice

Hemmen F; W. Mahana; Pierre Jollès; Alain Paraf

Embden goose (GEWL) and Barbary duck (DEWL) egg white lysozymes possess different amino acid sequences corresponding to the g-type and c-type, respectively. GEWL was shown to be a better immunogen than DEWL in both rabbits and mice. The antigenicity of the two lysozymes was tested using different technique (i.e. indirect ELISA, inhibition tests and immunoabsorption experiments). Injection of either GEWL or DEWL into rabbits and mice induced both specific antibodies and cross-reacting antibodies. Moreover, anti-GEWL antibodies, in contrast to anti-DEWL antibodies, did not cross-react with hen egg white lysozyme (HEWL), a c-type lysozyme. While the structure of GEWL was not modified after binding to plastic, DEWL was denaturated, but it did keep some native epitopes. It was concluded that g-type and c-type lysozymes, which have different amino acid sequences, exhibit strong common antigenic properties.


Biochemical and Biophysical Research Communications | 1976

The modification of (Na+ + K+) ATPase sensitivity to ouabain after extraction of membrane constituents distinct from the enzyme

Lionel Lelievre; D. Charlemagne; Alain Paraf

Summary The (Na+ + K+)ATPase from mouse plasmocytoma MOPC 173 ascitic cells was found to be resistant to ouabain in purified plasma membranes as 50 % of the enzyme activity (E 1/2) was inhibited by 120 μM ouabain. After 2 treatments by a sucrose-EDTA-imidazole buffer, the plasma membrane-bound enzyme recovered in the pellet was found to be much more sensitive to ouabain inhibition (E 1/2 = 0,4 μM). The original (Na+ + K+) ATPase sensitivity to ouabain can be restored by addition of concentrated supernatants from EDTA-treated membranes plus Ca++ and Mg++ to the pellet.


Biochimica et Biophysica Acta | 1973

Enzyme activities in membranes from three phenotypes of the murine plasmocytoma MOPC 173, cultivated in vitro

Lionel Lelievre; Alain Paraf

Abstract Cell surface and endoplasmic reticulum membranes were isolated from mouse plasmocytoma cells in culture. The distributions of membrane-bound enzyme activities over sucrose gradient fractions differed for epithelioid and fibroblastic cells. It is shown that microsomal enzymes are present in plasma membranes when isolated from contact-inhibition sensitive cells. When epithelioid cells reach confluence, a reduction in the enzyme activities of the plasma membrane fractions was found.


Journal of the Science of Food and Agriculture | 1990

Use of specific polyclonal antibodies to detect heat treatment of ovalbumin in mushrooms

Grish C Varshney; Alain Paraf

Abstract Using ovalbumin as a model protein in pure solution it was found that affinity chromatography of antisera against either native ovalbumin (NOA) or heat‐denatured ovalbumin (HDOA) gave four different antibody populations AC1 4 from each antiserum, with different binding properties to the related or unrelated antigen. Direct ELISA was shown to be useless for differentiating NOA from HDOA. Immunoprecipitation in solution is time consuming and, moreover, whereas NAC1 was shown to be specific for NOA compared with HDOA, DAC1, NAC2 and DAC2 were shown not to be fully specific for HDOA. In contrast, by using as capture antibodies either NAC3 or DAC4, a sandwich ELISA can be designed which is fully specific for NOA or HDOA, respectively. An approach to the identification of the temperature at which ovalbumin has been heated is described. This test will show whether ovalbumin has been heated to lower than 65°C or higher than 85°C. The test was applied to juices from canned mushrooms containing 2% ovalbumin.


Biochimica et Biophysica Acta | 1982

Characterization of a β-actinin-like protein in purified non-muscle cell membranes. Its activity on (Na+ + K+)-ATPase

Blandine Geny; Alain Paraf; Yann Fedon; Danièle Charlemagne

Abstract Treatment by EDTA of purified plasma membranes from MF2S cells (a variant of the murine plasmacytoma MOPC 173) solubilized proteins and increased by a 1000-fold the sensitivity of ( Na + + K + )- ATPase to ouabain. When added back with Ca2+ to treated plasma membranes, these EDTA-solubilized proteins restored the initial sensitivity of the enzyme to its inhibitor. We report the purification of a protein of M r 32 000, isolated from the EDTA-treated membrane supernatant. This protein was purified by a one-step procedure involving a preparative polyacrylamide gel electrophoresis without detergent. In the presence of Ca2+ it was able to restore the original sensitivity to ouabain of ( Na + + K + )- ATPase from EDTA-treated membrane. This protein was shown to be similar to the β-actinin described by Maruyama by the following criteria: (1) molecular weight and amino acid composition; (2) cross-reactivity with their respective antisera; (3) in the presence of Ca2+ the same quantitative biological activity on ouabain sensitivity of the ( Na + + K + )- ATPase . A possible interaction between β-actinin, calmodulin and membrane-bound ( Na + + K + )- ATPase is discussed.


Biochimica et Biophysica Acta | 1976

Plasma membrane studies on drug-sensitive and -resistant cell lines. II. Ouabain sensitivity of (Na+ +K+)-stimulated Mg2+-ATPase.

Lionel Lelievre; Danièle Charlemagne; Alain Paraf; Gitty Jonkman‐Bark; Vladimir Zilberfarb

Mutant cell lines have been selected from the murine plasmocytoma MOPC 173 for their resistance to ouabain, dibutyryl cyclic AMP, theophyllin and concanavalin A. We have compared three wild-type cell lines with their seven resistant counterparts. All resistant mutants exhibited a (Na+ + K+)-stimulated Mg2+-ATPase resistance to ouabain inhibition when measured in microsomes. The homogeneity of ouabain binding sites has been found in most of the cell lines; however, two different populations of sites have been detected in one wild-type and in one resistant cell lines. These results led us to hypothetise the (Na+ + K+)-ATPase-ouabain interaction being modulated by a non-specific membrane structure.

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Alain Zachowski

Centre national de la recherche scientifique

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Danièle Charlemagne

Institut national de la recherche agronomique

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Alain Zachowski

Centre national de la recherche scientifique

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Blandine Geny

Institut national de la recherche agronomique

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Fabienne Hemmen

Institut national de la recherche agronomique

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W. Mahana

Institut national de la recherche agronomique

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Dominique Pantaloni

Centre national de la recherche scientifique

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Hélène Saunal

Centre national de la recherche scientifique

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