Dissertations / Theses on the topic 'Biochimique'
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Lemaire, Géraldine. "Interactions "récepteurs-pesticides" : rôle dans la régulation des gènes de défense cellulaire." Nice, 2004. http://www.theses.fr/2004NICE4018.
The widespread use of pesticides has raised public health concerns. BY their affinity for certain nuclear receptors some pesticides widely used until the 1970’s but now banned may be regarded as xeno-hormones that may control vital genes. Within this framework, we initially examined the ability of various families of pesticides t activate or to inhibit androgen receptor (AR) and estrogen receptors (ERs) : only organochlorines have AR antagonist and ER agonist properties. The activation of retinoic acid receptor (RARa, b, g) was also tested : five organochlorine pesticides transactivate ARb and RARg and also induce cytochrome P450RAI1 expression. In addition, we were also interested in the pregnane X receptor (PXR) and a stable cellular model containing the receptor and its responsive element coupled to a luciferase gene reporter was developed. Some of the pesticides tested are PXR agonists and induce the expression of cytochrome P450 3A4 and 2B6 in cultured human hepatocytes. In the second part, the role of AhR in the thiabendazole-mediated induction of cytochrome P450 A1 (CYP1A1) was investigated. The pesticide induces transcriptional expression of CYP1A1, without displacement of [3H]TCDD from its binding sites to AhR, showing that a receptor could be indirectly activated by pesticides. All these results demonstrate that some pesticides founds in the environment interact with nuclear receptors, these interactions may explain their toxicological incidence in human health
Camponovo, Jérémy. "Synthèse de nanoarchitectures à vocation biochimique." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14042/document.
A new easily accessible trialkyne phenol dendron has been developed mimicking the already known triallyl phenol dendron. A family of polyalkynyl containing dendrimers with 27, 81 and 243 terminal branches was obtained starting from the classical polyiodo dendritic cores of the laboratory. Ferrocenes were then grafted using “click” chemistry. The dendrimers obtained allowed electrochemical sensing of both biologically interesting oxo-anions like ATP and metallic cations. Robust and recyclable modified platinum electrodes were obtained thank to the adsorption properties of large dendrimers. These electrodes are able to recognize the same ions as the dendrimer in solution. A novel series of glycodendrimers with 27, 81 and 243 modified xylopyranosides termini was synthesized too. The characterization methods for such nanoobjects were investigated, and particularly technics that allow to obtain the size of the molecules like dynamic light scattering (DLS) and DOSY NMR. Finally, a family of robust polyalkynyl containing dendrimers with 4 to 6 enlarged branches was developed. The functionalization with randomly methylated beta-cyclodextrins using “click” chemistry is also reported
Sansot, Jean-Luc. "Alanine aminopeptidase approches biochimique et toxicologique /." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb376010389.
DOE, CURT SYLVIE. "Evolution botanique et biochimique des renonculacees." Strasbourg 1, 1987. http://www.theses.fr/1987STR10718.
Seffouh, Amal. "Caractérisation biochimique et fonctionnelle de l'enzyme HSULF." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV014.
Heparan sulfate (HS) is a polysaccharide able to bind and modulate a wide variety of proteins. HS large interactive properties are essentially governed by precise sulfation patterns of the polysaccharide. Sulf-1 and Sulf-2 are two endosulfatases able to cleave specific 6-O sulfate groups within HS chains. Their action can modulate critical intracellular signaling processes, many of which with key relevance for cancer development. However, little is known on their structure, substrate specificities, and on the way their catalytic activity directs the subtle modifications of HS 6-O-sulfation profile.In this work, we have identified an original enzymatic mechanism by which Sulfs catalyze the processive and orientated desulfation of HS and finely regulate the polysaccharide biological properties. We also identified two basic motifs within the N-terminal domain of HSulf-2. Recombinant enzymes mutated for these sites were then produced and characterized. We found that these epitopes are necessary for its endosulfatase activity. Altogether, these results provide further insights into the enzyme/substrate recognition process and contribute to the understanding of the fundamental role played by these enzymes in the regulation of HS activity. The biochemical study of the purified HSulf-2 allowed to highlight a O-glycosylation able to significantly modulate its activity at the cell surface. Otherwise, and in collaboration with the Karolinska Institute (Stockholm, Sweden), the study of malignant mesothelioma (MM) provided new evidence that enhanced Syndecan-1 expression also finely modulates HS structure by interfering with HS-modifying enzymes HSulf-1. These results suggest important roles for Syndecan-1 and HSulf-1 in MM
Muir, Kyle. "Caractérisation biochimique et biophysique du complexe cohésine." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV005/document.
Sister chromatid cohesion is a fundamental prerequisite to faithful genome segregation. Cohesion is precisely regulated by accessory factors that modulate the stability with which the cohesin complex embraces chromosomes. One of these factors, Pds5, engages cohesin through Scc1 and participates both in the enhancement of cohesion, and conversely in mediating the release of cohesin from chromatin. In this thesis the crystal structure of a complex between budding yeast Pds5 and Scc1 is presented, thus elucidating the molecular basis of Pds5 function. Pds5 forms an elongated HEAT repeat that binds to Scc1 via a conserved surface patch. Through complementary cell biological and biochemical characterisation of this structure, the thesis demonstrates that the integrity of the Pds5–Scc1 interface is indispensable for the recruitment of Pds5 to cohesin, and that its abrogation results in loss of sister chromatid cohesion and cell viability. The results presented in this thesis therefore suggest that Pds5 is a constitutively bound, core subunit of cohesin
Rosenberger, Corinne. "Etude biochimique de l'autisme : analyse linéaire discriminante." Paris 5, 1988. http://www.theses.fr/1988PA05P243.
Pivot, Véronique. "Etude biochimique et activité de phospholipides fongiques." Lyon 1, 1991. http://www.theses.fr/1991LYO10039.
Lazrak, Tarik. "Renforcateurs membranaires : etude structurale et evolution biochimique." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13167.
Lazrak, Tarik. "Renforçateurs membranaires étude structurale et évolution biochimique /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37607103c.
JEBLAOUI, KARIMA. "Contribution biochimique au diagnostic de la mucoviscidose." Strasbourg 1, 1987. http://www.theses.fr/1987STR10732.
FERRERO, LUCIA. "L'adn topo-isomerase iv de staphylococcus aureus : identification, caracterisation biochimique et, etudes biochimiques et genetiques sur la resistance aux fluoroquinolones." Paris 7, 1995. http://www.theses.fr/1995PA077289.
Cotton, Frédéric. "Contribution au diagnostic biochimique des anémies hémolytiques héréditaires." Doctoral thesis, Universite Libre de Bruxelles, 2003. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211269.
Leclerc, Marie-Claude. "Purification et caractérisation biochimique d'une nucléotidase d'origine hépatique." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0015/MQ56927.pdf.
Leclerc, Marie-Claude. "Purification et caractérisation biochimique d'une nucléotidase d'origine hépatique." Mémoire, Université de Sherbrooke, 1998. http://savoirs.usherbrooke.ca/handle/11143/4437.
Hündling, Dörte. "Caractérisation biochimique et structurale de lectines d'Aspergillus fumigatus." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV055/document.
The aim of this thesis was to contribute to the understanding of infection strategies of the opportunistic pathogen Aspergillusfumigatus. This pathogenic mould is an emerging cause of morbidity and mortality in immuno-compromised patients and hospital environments. An infection with Aspergillus is generally referred to as Aspergillosis; it can develop in a variety of organs but the most common sites are the respiratory apparatus i.e. lungs and sinuses. Besides infections (invasive aspergillosis), colonization with the fungus can cause allergic reactions (allergic broncho pulmonary aspergillosis) and asthma. The number of immuno-suppressed patients is steadily increasing due to advancement in the HIV, cancer and cystic fibrosis medical care, as well as an increasing number of organ transplantations. Needless to say that new antifungal drugs and preventive medication is desperately needed to support medical care for those patients. Even though several fungicides already exist on the market, invasive aspergillosis remains to be often fatal. On one hand, this is due to difficulties in diagnosis and on the other hand, resistances are emerging rapidly. The motivation behind this thesis is to understand the underlying mechanisms that are involved in the first contact between conidial spores and host tissues. Initial adhesion steps often involve carbohydrate binding proteins, called lectins. They recognize glycoconjugates such as glycoproteins, glycolipids and glycosaminoglycans which cover the epithelial tissue and mucosal surface of the respiratory tract.. Identification and characterization of the lectins from A. fumigatus will therefore contribute to the understanding of the glycostrategy of this opportunistic pathogen and of the mechanisms involved in adhesion and infection. Detailed structural analysis of the carbohydrate-protein interactions will allow ascertaining the lectins role in virulence and guide the design of glycomimetics, as adhesion inhibitors. With this novel approach of targeting the pathogen adhesion rather than its proliferation, resistances are believed to be less frequent due to the lack of evolutionary pressure. In this work, two different strategies were employed to obtain novel lectins. Firstly, lectins were purified from crude fungal extracts and secondly the A. fumigatus genome was screened for encoded proteins showing sequence similarity with known fungal lectins. While lectin purification from the crude extracts was inconclusive due to low lectin activity in the starting material, genome screening showed that several putative lectins were present. One of these lectins, named AFL6, belonged to the cyanovirin-N homolog (CVNH) family and it was recombinantly expressed and purified. Glycan array and micro calorimetry techniques were carried out to investigate its carbohydrate binding specificityand the three dimensional structure was determined using X-ray crystallography. The structure showed an overall similarity with other CVNHs with slight differences in the presumed carbohydrate binding sites. Unlike other family members, it shows a low affinity for mannosides and an apparent affinity for lactosamine containing glycan structures
Villar, Marc. "Incompatibilité interspécifique chez Populus : approches physiologique et biochimique." Lyon 1, 1987. http://www.theses.fr/1987LYO10008.
Moummi, Chafiq. "Caractérisation pharmacologique et biochimique des myocytes gastriques isolés." Montpellier 1, 1987. http://www.theses.fr/1987MON13507.
LAGAUDRIERE, GESBERT CECILE. "Caracterisation biochimique et fonctionnelle de la tetraspanine cd82." Paris 11, 1997. http://www.theses.fr/1997PA112138.
GENDY, CYRILLE. "Controle de la morphogenese : etude physiologique et biochimique." Paris 11, 1991. http://www.theses.fr/1991PA112280.
DEZEURE, FRANCOISE. "Etude biochimique des analogues fluores de la putrescine." Université Louis Pasteur (Strasbourg) (1971-2008), 1989. http://www.theses.fr/1989STR13006.
Quintyn, Jean-Claude. "Approche chimique et biochimique du décollement de rétine." Toulouse 3, 2007. http://thesesups.ups-tlse.fr/161/.
Chemical and biochemical approach to the retinal detachment The retinal detachment may blind if it is not treated by surgical operation. With a chemical and biochemical approach, we have tried to improve the anatomical and functional results of this pathology. We report a clinical study about the results of Oxane HD(r) use in the treatment of the retinal detachment. Oxane HD(r) is a mixed of silicone oil 1300 and a mixed olefin C8F17CH2CH=CHCH2CH(CH3)2 called RMN3. Its density is upper than one. We have showed that the concentration of the Neuron Specific Enolase in the subretinal fluid is correlated with the death of the photoreceptors. Finally, we report that the sphingosine-1-phosphate inhibits the photoreceptors apoptosis during a retinal detachment. We propose a formulation of this molecule for a topic use in an apoptosis corneal model
Leclerc, Marie-Claude. "Purification et caractérisation biochimique d'une nucléotidase d'origine hépatique." Sherbrooke : Université de Sherbrooke, 1999.
Villar, Marc. "Incompatibilité interspécifique chez Populus approches physiologique et biochimique /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376106080.
Nayak, Ananta Kumar. "Modélisation de la circulation sanguine et signalisation biochimique." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALY094.
In our body, red blood cells (RBCs) are primarily involved in transporting oxygen and nutrients to the tissues, and conversely, they become the transporter of metabolic excreta such as carbon dioxide from the tissues. In addition to these passive processes, RBCs are actively participated in communication with the vascular wall. This communication is mediated by a signalling molecule, adenosine triphosphate (ATP), which is released as a result of the shear stress experienced by the RBC membrane. ATP is known as an energy carrier, and the energy it releases by hydrolysis of the phosphate bond is used to carry out cellular functions. However, the ATP released to the plasma by RBCs triggers a cascade of biochemical reactions in endothelial cells (ECs), resulting in the release of sequestered Ca2+ from the endoplasmic reticulum (ER). Ca2+ is a ubiquitous ion responsible for numerous cellular functions such as vasodilation, cell proliferation and gene transcription. In particular, Ca2+ regulates the synthesis of nitric oxide (NO), an important vasodilator, in the vascular wall. NO molecules act on smooth muscle cells (SMCs), a layer located beneath the endothelium layer, to relax the vessel wall diameter. As a result, increased vessel diameter results in improved blood supply to the area where metabolic needs are high. Nevertheless, the concentration of NO available for SMC relaxation is also affected by RBCs, as they act as scavengers by converting it into other metabolites such as nitrites and nitrates. Because of the aforementioned importance of RBC dynamics and its impact on biochemical signalling in the vascular wall, it is necessary to understand the fundamentals of local blood perfusion control and progression of vascular diseases. This thesis is mainly devoted to the coupling of RBC dynamics and biochemical signalling occurring in the vascular wall using immersed boundary lattice Boltzmann method (IBLBM). More specifically, we investigated the effect of RBC dynamics in a two-dimensional straight channel (2-D) with changes in parameters such as flow strength, channel width, and RBC concentration on the Ca2+ and NO dynamics. More elaborately, firstly, we developed a minimal homeostatic Ca2+ dynamics model which ensures the return of intracellular Ca2+ concentrations from its non-physiological concentration to the physiological concentration in the presence of agonist (ATP). Secondly, we explicitly integrated ATP released from RBCs and ECs that triggers Ca2+ signalling in the endothelium. This study sheds light on the upstream control of blood perfusion in a vascular network due to the propagation of Ca2+ signals from a region of higher ATP concentration to region of lower ATP concentration. Lastly, we further modelled both ATP and shear stress-dependent NO synthesis in ECs. This model is extended to explicitly incorporate the scavenging of NO by RBCs in order to understand NO availability in blood vessels with a 2-D numerical setting. This study highlights the fact that the concentration of NO in the vascular wall strongly depends on the concentration of RBCs
Passareiro, Heloisa M. "Contribution à la caractérisation biochimique de protéines du cytosquelette." Doctoral thesis, Universite Libre de Bruxelles, 1990. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/213128.
Bouchard, Dominique. "Caractérisation biochimique de l'intégrase de l'intégron de Treponema denticola." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/23650/23650.pdf.
Aizel, Kaheima. "Étude Structurale et Biochimique d'un Facteur d'Échange Atypique d'Arf." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-01037875.
Franc, Jean-Marie. "La mésoglée des cténaires : approches ultrastructurale, biochimique et métabolique." Lyon 1, 1985. http://www.theses.fr/1985LYO10034.
Oaxaca, Castillo David Alonso. "L'Acyl-CoA oxydase 1 humaine : caractérisation biochimique de l’enzyme." Dijon, 2007. http://www.theses.fr/2007DIJOS010.
Human acyl-CoA oxidase 1 (ACOX1) is a rate-limiting enzyme in peroxisomal fatty acids B-oxidation and its deficiency is associated with a lethal, autosomal recessive disease, called pseudoneonatal-adrenoleukodystrophy. Two mRNA variants, transcribed from a single gene encode ACOX1a or ACOX1b isoforms respectively. Recently, a mutation in a splice site has been reported, which results in the defective peroxisomal beta-oxidation of C26:0. Here we show that both mRNA splice variants are expressed in human liver and we investigated the biochemical role of the two human ACOX1 isoforms by heterologous expression of the catalytically active ACOX1a and ACOX1b enzymes in E. Coli. ACOX1a seems to be more labile and exhibits only 50% specific activity toward palmitoyl-CoA as compared to ACOX1b
VAUDEQUIN-DRANSART, VALERIE. "Etude biochimique et moleculaire de nouvelles souches d'agrobacterium tumefaciens." Paris 6, 1996. http://www.theses.fr/1996PA066424.
MARTIN, ANNE-CELINE. "Production et caracterisation biochimique de la tubuline gamma recombinante." Toulouse 3, 1997. http://www.theses.fr/1997TOU30211.
Gachon, Anne-Marie Françoise. "Liquide lacrymal : etude biochimique des proteines, interaction proteines-biomateriaux." Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2E387.
Chappuit, Lucrezia. "Design, synthèse et évaluation biochimique d’inhibiteurs des ADN Méthyltransférases." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS372.
This manuscript presents the development of novel DNMT1 (DNA Methyltransferase) inhibi- tors. This enzyme is involved in epigenetic modification of DNA and its deregulation may lead to epigenetic cancers. The first part of this work focused on the design by molecular modeling of new prolino-homo-tryptophan compounds which can interact with both pockets of DNMT1. In a second time, molecular modeling allows us to design several pyrazole compounds as po- tential new DNMT1 inhibitors. Following these studies, all designed compounds were synthe- tized and tested on a recombinant human DNMT1enzyme thanks to a biochemical inhibition test. Biological evaluation bright to light two lead compounds which totally inhibit DNMT1 at high concentration (500 μM)
Simon, Nathalie. "Les picoeucaryotes photosynthetiques oceaniques : caracterisation morphologique, biochimique et genetique." Paris 6, 1995. http://www.theses.fr/1995PA066209.
PEBORDE, JEAN PASCAL. "Etude biochimique et immunologique du lipopolysaccharide d'escherichia coli k12." Toulouse 3, 1989. http://www.theses.fr/1989TOU30074.
DOLINSEK, AVRELIJA. "Etude biochimique et biologique de l'interferon - gamma trophoblastique porcin." Paris 11, 2000. http://www.theses.fr/2000PA112297.
Duhamel, Rémi. "Etude d'un capteur biochimique à ondes acoustiques de lamb." Besançon, 2005. http://www.theses.fr/2005BESA2020.
The studied system is a microbalance which uses acoustic waves properties to detect mass variations. When Lamb waves are excited in a membrane, the vibrating frequency of the membrane is linked to its own mass. If a small mass quantity is added to the membrane the vibrating frequency will change and we will be able to detect this frequency shift. Lamb waves are really interesting as a basis for such a device because for a particular mode and under given conditions there is nearly no energy loss in liquid media and mass sensitivity is better than the one reached by quartz crystal microbalances. We have decided to study two particular aspects of such a system : how to reduce temperature sensitivity and how to increase mass sensitivity. Regarding temperature sensitivity, two different kinds of systems have been studied. A first system using electrostatic excitation has been built. Another system using piezoelectric excitation has also been realised. This system is made of two crossed delay lines on the same membrane. With such a system it is possible to retrieve both temperature and mass variations at the same time. As far as mass sensitivity is concerned, we wanted to reduce the membrane thickness where waves are propagating. Two kinds of devices have been studied, one using PZT as piezoelectric material, the other one using AlN. AlN devices do work as expected, and in liquid media the microbalance shows a 200 cm2/g mass sensitivity for a 13 MHz oscillating system
Biegala, Isabelle. "Productivite zooplanctonique dans les ecosystemes marins : approche biochimique (atcase)." Aix-Marseille 2, 1998. http://www.theses.fr/1998AIX22080.
Liénard-Lambour, Barbara. "Caractérisation biochimique de macroH2A1.1 dans les cellules cancéreuses mammaires." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30273.
Biochemical properties of chromatin can be modulated by incorporation of histone variants in chromatin. MacroH2A has a amino-terminal domain typical of a full-length H2A, fused to a "macro domain". To date, three macroH2A have been identified: macroH2A1.1 and macroH2A1.2 which are alternative spliced variants and macroH2A2. They have been principally associated to heterochromatin formation and transcriptional repression. State of art shows that macroH2A1 is associated to various cellular mechanisms such as chromosome X inactivation, senescence, cellular development, transcriptional regulation and DNA double strand breaks. Many of these processes are implicated in cancer formation, making macroH2A1 an important element to consider. Its expression has also been correlated to numerous cancer developments such as lung, colon, skin or breast. Due to the structural differences, links to ligands and controversy observed in the literature between macroH2A1.1 and macroH2A1.2, it seems essential to study separately these two variants without omit their interconnection significance. Recently, we have determined that macroH2A1.1 expression level correlated specifically with Triple Negative Breast Cancer (TNBC). At the molecular level, this combination results in a positive correlation between macroH2A1.1 expression level and molecular characteristics of Epithelio-Mesenchymal Transition (EMT). In this context, the aim of my thesis was to identify biochemical properties of macroH2A1.1 in many breast cancer cellular models using a specific antibody for macroH2A1.1 generated in the lab. All this work has allowed the identification of a mono-ubiquitinated form of macroH2A1.1 on its lysine 123. Technical tools implemented have also allowed to identify the modified form in association with RNA:DNA duplexes. The results presented in this thesis will allow to better understand the importance of post-translational modification of histone variant and to open a new operating field in the role definition for this variant
Berta, Philippe. "Myocytes aortiques en culture primaire caractérisation biochimique et pharmacologique." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595993k.
Hamdaoui, Ahmed. "Contribution biochimique à l'étude du rôle pathologique des élastases." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37598179j.
Aizel, Kaheima. "Étude structurale et biochimique d’un facteur d’échange atypique d’Arf." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA114827/document.
Small GTPases of the Arf family, which are pivotal regulators of membrane traffic in eukaryotes, are activated by several families of guanine nucleotide exchange factors (ArfGEFs). ArfGEfs play a key role in processing upstream regulatory signals that lead to Arf activation onto specific subcellular compartments, yet the mechanisms by which they target activated Arfs to specific membranes and their coordination with nucleotide exchange remain poorly understood. Here we used X-ray crystallography and reconstitution of ArfGEF activities on artificial membranes to analyze these mechanisms for an atypical human ArfGEF, involved in receptor endocytosis and associated with tumour invasion in various cancer cells. Members of this family have been described as Arf6-specific GEFs, and carry a PH-like domain downstream their Sec7 domain. In a second part of the work we wanted to know how the isoforms Arf1 and Arf6 achieve exquisitely specific functions in cells. Arf1 and Arf6 are highly similar: they have over 60% sequence identity, and structural studies have shown that the surfaces they use to interact with regulators and effectors are essentially identical in sequence and structure. Yet, they have non-overlapping functions in cells. Arf1 is a major regulator of most aspects of vesicular traffic, while Arf6 is restricted to the plasma membrane where it acts at the crossroads of trafficking and cytoskeleton functions (D'Souza-Schorey and Chavrier 2006). Consistent with their cellular specificities, Arf1 and Arf6 also have distinctive biochemical properties in vitro, for which no straightforward structural explanation has been put forward. Here we used X-ray crystallography, synchrotron SAXS experiments and NMR to assess the difference between these two isoforms
Cholet, Orianne. "Etude de l'écosystème fromager par une approche biochimique et moléculaire." Phd thesis, INAPG (AgroParisTech), 2006. http://pastel.archives-ouvertes.fr/pastel-00003111.
Ducassou, Lionel. "Etude biochimique d’un cytochrome P450 de cerveau humain : le CYP2U1." Thesis, Paris 5, 2012. http://www.theses.fr/2012PA05P642/document.
Among the 57 human cytochrome P450 genes that have been identified; substrates, structure and physiologic role of 15 of them is practically unknown. They are called orphan. One of them, CYP2U1 is one of the most expressed cytochrome P450 in the brain and in the cerebellum but also one of the most conserved isoform in the all animal kingdom. This manuscript first describes the optimization of the heterologous expression of an active form of CYP2U1. Expression in a eukaryotic host, yeast Saccharomyces Cerevisiae first allows the production of a catalytic active CYP2U1-P450 reductase complex needed for substrate screening. Another expression system in a prokaryote host Escherichia Coli will allow higher production rate of a truncated and soluble form of the protein which will permit structural studies. Then a directed substrate screening was performed with the liquid chromatography – mass spectrometry analysis of CYP2U1 incubations. To date, 70 molecules, CYP2 family substrates, were tested that allow the identification of the two first exogenous CYP2U1 substrates: débrisoquine and terfenadone analogs. A structural study was achieved using a homology tridimensional model of the enzyme. We have found that CYP2U1 is longer than the other human CYPs, with an N-terminal 20 amino acids insertion, located after the helical membrane spanning domain. Structural models were built using six crystallized human CYP2s as templates. Molecular dynamics experiments in membrane suggested a specific interaction with the membrane. The active site topology and the access channels were also determined and a docking of the two first exogenous CYP2U1 substrates was performed in order to confirm the regioselective hydroxylation activities observed in vitro
Ducassou, Lionel. "Etude biochimique d'un cytochrome P450 de cerveau humain : le CYP2U1." Phd thesis, Université René Descartes - Paris V, 2012. http://tel.archives-ouvertes.fr/tel-00799083.
Tardif, Maxime. "Analyses biochimique et protéomique de la poly (ADP-ribosyl)ation." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27718/27718.pdf.
Corbeille-Magnol, Chantal. "Etude biochimique de l'état de dénutrition chez le jeune enfant." Paris 5, 1989. http://www.theses.fr/1989PA05P194.
Susplugas, Claudine. "Etude pharmacodynamique, biochimique, chimique et botanique de reseda phyteuma l." Montpellier 1, 1985. http://www.theses.fr/1985MON13506.
Dhouib, Rabeb. "Etude biochimique, structurale et physiologique d’enzymes lipolytiques chez les Mycobactéries." Aix-Marseille 2, 2009. http://theses.univ-amu.fr.lama.univ-amu.fr/2009AIX22093.pdf.
Lipolytic enzymes in Mycobacterium tuberculosis, the etiologic agents of tuberculosis, remain poorly studied despite their probable involvement in bacteria cell life. Genomic DNA from M. Tuberculosis analysis has permitted the identification of genes encoding lipolytic enzymes. My thesis work was consisted, on the one hand, of biochemical, structural and physiological characterization of Rv0183, a putative lipolytic enzyme from M. Tuberculosis. We have demonstrated that Rv0183 is a monoacylglycerol lipase which is located not only in the cell envelope but also in the culture medium filtrate. The physiological function of Rv0183 was assessed by studying its ortholog in M. Smegmatis, the MSMEG_0220. It has been shown that this protein was involved not only in the exogenous lipid degradation but also in the cell envelop architecture. On the other hand, we have investigated on the biochemical characterization of two secreted proteins of M. Tuberculosis belonging to the cutinase family, Rv1984c and Rv3452. Despite 50% identity in their amino acid sequence, these enzymes show distinct substrate specificities. Rv1984c hydrolyses carboxyl esters and monoacylglycerols whereas Rv3452 behaves as a phospholipase A2 able to induce macrophage lysis suggesting an implication of this enzyme in M. Tuberculosis virulence. Finally, we have studied the in situ lipolysis in M. Smegmatis. Thanks to time-lapse fluorescence microscopy, we have monitored the intracytoplasmic lipids hydrolysis in this bacterium incubated under nutrient starvation. Lipid degradation was inhibited by tetrahydrolipstatin confirming the involvement of lipolytic enzymes in this process