Letteratura scientifica selezionata sul tema "Peptide chélateur de métaux"
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Articoli di riviste sul tema "Peptide chélateur de métaux":
Lacaze, J. C., A. Chesterikoff e B. Garban. "Bioévaluation de la pollution des sédiments de la Seine (région parisienne) par l'emploi d'un bioessai basé sur la croissance à court terme de la micro-algue Selenastrum capricornutum Printz". Revue des sciences de l'eau 2, n. 3 (12 aprile 2005): 405–27. http://dx.doi.org/10.7202/705037ar.
Tesi sul tema "Peptide chélateur de métaux":
El, Hajj Sarah. "Methodologies for Screening Metal-Chelating Peptides in Protein Hydrolysates for their Antioxidant Properties". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0031.
Currently, the discovery of new biomolecules is essential for various industrial applications. Peptides produced by hydrolysis of plant or animal proteins are of interest because of their potential bioactivities. Some peptides, by their ability to complex iron(II), can inhibit and slow down oxidation phenomena. To date, the discovery of new bioactive molecules is generally based on long and fastidious empirical approaches, involving large quantities of solvents, harmful to the environment. Therefore, it is important to develop new and highly sensitive screening methods before implementing a selective separation process of these peptides of interest present in mixture. The objective of this thesis is therefore to (i) develop highly sensitive screening methods to identify the presence of these metal chelating peptides (MCPs) in hydrolysates, produced in the laboratory, before undertaking a time-consuming separation phase and (2) to study their antioxidant activities, using biochemical and cellular assays. In the first approach, time-resolved molecular dynamics (switchSENSE) was first implemented on model peptides capable of complexing metals and then applied to non-filtrated soy and tilapia protein hydrolysates. It has proven to be very sensitive for detecting the presence of MCPs in peptide hydrolysates. This technology is based on the electrical movement of DNA strands, present on the surface of gold microelectrodes, on which are immobilized metal ions. When a peptide has an affinity for an immobilized metal ion and thus forms a peptide-metal complex, this results in a variation of the measured fluorescence signal. On the other hand, MCPs were screened in ultrafiltrated soy and pea protein hydrolysates using Surface Plasmon Resonance (SPR). This advanced technique, allows to determine an affinity constant between a peptide and a metal ion immobilized on a microchip at the molecular scale. It is used here in an original way to study different hydrolysates and thus screen the best hydrolysis condition to produce MCPs. The biological interest in exploring metal-chelating activity in these hydrolysates is to evaluate their antioxidant power in cellulo. These peptides could be promising for ferroptosis inhibition by chelating excess iron ions and thus contribute to the prevention of cell death in several diseases including Atherosclerosis (AS). We aimed to develop a ferroptosis model (induction and rescuing) on human aortic smooth muscle cells to mimic ferroptosis happening during AS development. The ferroptosis model was developed in three steps taking into consideration three essential parameters such as the concentration of ferroptosis inducers (Erastin and ferric ions), the time and the medium of incubation. At each step, 2 biomarkers i.e. intracellular concentration of GSH and lipid peroxidation were followed by NDA and TBARS methods, respectively. The rescue of the ferroptosis model was validated using metal chelators such as DFO and DFr, which are also control molecule regarding MCP activity
Deraeve, Céline. "Synthèse et évaluation biologique de dérivés polyquinoléine chélateurs d'ions métalliques en relation avec la maladie d'Alzheimer". Phd thesis, Université Paul Sabatier - Toulouse III, 2006. http://tel.archives-ouvertes.fr/tel-00142741.
Irankunda, Rachel. "Nickel Chelating Peptides & Chromatography : From Peptides Separation Simulation up to their Antioxidant Activities - related Applications". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0213.
Metal-Chelating Peptides (MCPs), from protein hydrolysates, present various applications in nutrition, pharmacy, cosmetic etc. Yet, the empirical approach generally used to discover bioactive peptides from hydrolysates is time consuming and expensive due to many steps of fractionation, separation and biological activities evaluation. Thus, this PhD aimed to develop a novel approach for MCPs separation prediction using chromatography modelling and simulation based on the analogy between Immobilized Metal ion Affinity Chromatography (IMAC) and Surface Plasmon Resonance (SPR). For the first time, the SPR-IMAC analogy was experimentally investigated on 22 peptides and 70% of them validated this analogy, since peptides well retained in IMAC were also endowed with a good affinity for Ni2+ in SPR. In the second time, peptides with high affinity for Ni2+ (i.e low dissociation constant KD in SPR and a high retention time in IMAC) were used to study the modelling and simulation of peptide concentration profiles at the column outlet in IMAC. Since knowledge of adsorption isotherms was required to perform simulation, it was necessary to develop a methodology for predicting Langmuir isotherm parameters in IMAC from SPR data. The validity of simulation was evaluated by comparing experimental and simulated retention times that should be close for reliable prediction. Therefore, several approaches were evaluated to determine Langmuir sorption parameters, the most interesting one introduces a correction factor on the maximum adsorption capacity qmax alone, assuming that the affinity of peptides for immobilized Ni2+ did not change depending on the technology used (SPR vs. IMAC), thus affinity constant KA was not modified. Meanwhile, industrial application of MCPs and hydrolysates were studied. First, pea protein hydrolysates were produced by either Alcalase® followed by Flavourzyme® (Alc+Flav≤1kDa) or Protamex® followed by Flavourzyme® (Prot+Flav≤1kDa). SwitchSENSE® technology evidences the presence of Ni2+ chelating peptides and antioxidants tests showed that Prot+Flav≤1kDa has higher radical scavenging and reducing power, related to its higher degree of hydrolysis and small-size peptides quantity. Secondly, pea hydrolysates and MCPs were investigated for their ability to inhibit the lipid oxidation in emulsions. They slowed down lipid oxidation through chelation of prooxidant (metals such as Fe2+) reducing primary and secondary oxidation products responsible of deterioration of lipid containing products. Thus, pea hydrolysates and MCPs could be used as antioxidants in food and cosmetic products, as alternative to chemicals such as EDTA, BHT and TBHQ
Paris, Cédric. "Développement de nouvelles approches analytiques pour le criblage de peptides chélateurs de fer". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0088.
Faced with the growing need for new bioactive compounds of natural origin, by-products from the agro-food industry and the processing of agro-resources constitute a strategic resource to be exploited. In fact, the enzymatic hydrolysis of plant or animal proteins makes it possible to generate a wide variety of peptide sequences with potential biological properties: antihypertensive, antithrombotic, anticancer, opioid, antimicrobial. Despite the bioactive potential of certain peptides, their uncertain presence and their low concentration in a protein hydrolysate (a complex mixture sometimes made up of more than a hundred peptides) limit their purification and use. Also, bioactive peptides could be screened before their purification in order to initiate the separation step only if activity is proven. Antioxidant power is a generic term which groups together various chemical mechanisms such as anti-free radical activity, inhibition of lipid peroxidation, or even metal chelation. By chelating the transition metals naturally present in vivo (iron, copper), the chelating peptides could be used as indirect antioxidants and thus act against oxidative stress. The main objective of this PhD thesis is to develop original methods for high throughput screening of iron-chelating peptides present in protein hydrolysates. Ultimately, these methods could be applied to all types of complex peptide mixtures. The first approach is based on immobilized metal affinity chromatography (IMAC). IMAC is a reference technique for purifying metal-chelating peptides in hydrolysates. Thanks to the specificity of interaction between a given metal – immobilized on the stationary phase IMAC – and determined complexing groups, it is possible to selectively identify the chelators present in complex mixtures. Our objective being to achieve a rapid detection of these molecules of interest, we carried out an on-line coupling with mass spectrometry (MS). The second strategy consists of evaluating the formation of iron-peptide complexes in solution. In this case, all the electron acceptor sites of the metal are accessible (unlike the IMAC technique which presents a potential bias from this point of view) and, on the other hand, the solubilization conditions can simulate the target medium (i.e. the intracellular medium). In addition, the observation of the peptidic form complexed with iron (FeII or FeIII) provides direct and irrefutable proof of the chelating capacity of a peptide. Thus, the identification of a chelating peptide can be carried out by the concomitant detection of its free form (peptide) and of its complexed form (iron-peptide). In this approach, mass spectrometry – thanks to its sensitivity and its specificity - is a technique of choice for carrying out the desired screening. After having been tested on synthetic peptides (pure solutions and mixture), the two protocols were applied to a real protein hydrolysate. The preliminary results are promising and make it possible to envisage, in the short term, the automated screening of various real hydrolysates for the search for iron(II)- and iron(III)-chelating peptides
Vincent, Amandine. "Étude de complexes mimes de superoxyde dismutases : de la conception de nouveaux composés par chimie combinatoire jusqu’à l’exploration des voies d’administration sur modèle murin". Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEE049.
This PhD project is focused on the discovery of new SOD peptidyl mimics by combinatorial chemistry and the study of Mn1 complex delivery to mice. Mn1 is a small manganese II complex that shows great anti-superoxide and anti- inflammatory activities at different scales: in vitro, in cellula and on a mice model of colitis induced by DNBS. The use of MD007 bacteria as protecting bags improved significantly the effect of Mn1 as an anti-inflammatory therapeutic agent. Besides, new SOD mimics have been discovered by a combinatorial approach associated with a gel colorimetric screening. A peptidyl (OCP1) copper complex has been identified and fully characterized. It presents a very interesting activity on two cellular models and proves the efficiency of such combinatorial approach. Another peptidyl (DCP1) complex has been studied with manganese II. The structure has been progressively modified to improve both activity and affinity with the Mn(II). Finally, silica nanoparticles functionalized with the peptide DCP1 were synthesized and show very relevant in vitro activity
Tremblay, Geneviève. "Développement d’outils moléculaires pour la tomographie d’émission par positrons". Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/9857.
Abstract : PET is a powerful imaging modality that follows tiny labeled tracer concentrations for the detection of cancer and other pathologies. There currently is a growing interest for the development of peptides as diagnostic and treatment tools in oncology. This interest is justified by the fact that peptides are tolerant to the presence of bifunctionnal chelators or prosthetic groups for labeling with many radiometals (64Cu, T1/2 = 12,7 h, 68Ga, T1/2 = 68 min, etc.) or 18F (T1/2 = 109,8 min), without losing their biological activity. The objective of the work reported in this document was to develop innovative and efficient molecular tools that facilitate peptide labeling for PET imaging. Specifically, they are a bifunctionnal chelator and a fast and selective prosthetic group conjugation method. On the first aspect, a lysine analogue bifunctionnal chelator bearing methylhydroxamate ligands was synthesized in solution through a double bisalkylation. The preliminary results show a weak Cu(II) chelation, but they are to be pushed forward with 68Ga and 89Zr. On the second aspect of 18F radiolabeling, synthetic procedures were optimised for two steps, which are the prosthetic group’s labeling and its conjugation to the peptide. First, the labeling conditions for a SNAr reaction with 18F- were developed, to yield the necessary 18F-thioester prosthetic group. Then, its conjugation to the peptide by the chemical ligation reaction through its three steps 1) a favored transthioesterification between the thioester and thiol peptide segments; 2) an irreversible rearrangement of the thioester intermediate to a N-(oxyalkyl)amide, followed; 3) the auxiliary cleavage. By this work, it has been proven that the new one pot methodology accelerates the reaction and allows the 18F labeling of unprotected peptides, which limits secondary reactions and the number of post peptide labeling steps. The prosthetic group conjugation to both model compound and peptide takes place in 26-55 min, compared to the 48 h initially reported. The proposed method also allows the labeling of unprotected peptides. In the future, the bifunctionnal chelator and the prosthetic group will be conjugated to different peptide derivatives that target cancer implied receptors and competition, saturation, biodistribution and µPET imaging assays will be performed.
Bonnet, Célia. "Complexation des cations lanthanides trivalents par des ligands d'origine biologique pour l'IRM : structure, thermodynamique et méthodes". Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00089144.
Les ligands ACX et BCX, dérivés acides d'Α- et Β-cyclodextrines modifiées, forment des complexes mono et bimétalliques avec les Ln(III). Les complexes LnACX ou LnBCX ont des affinités similaires à celle de ligands triacides. La structure à l'état solide du complexe bimétallique Lu2ACX montre un enfouissement important des cations à l'intérieur de la cavité. En solution, pour le complexe LnBCX, une seule molécule d'eau est coordonnée au cation, ce qui nous a permis de mettre en évidence une importante contribution de seconde sphère à la relaxivité.
L'étude RMN du ligand peptidique issu de la famille des RAFT a montré qu'il coordonne les Ln(III), avec une affinité similaire à celle de ligands naturels dérivés de la calmoduline.Une étude relaxométrique a également mis en évidence une importante contribution de seconde sphère à la relaxivité.
Pour mieux comprendre les facteurs moléculaires compliqués affectant la relaxivité, nous avons développé de nouvelles méthodes relaxométriques, basées sur des solutés sondes. Ces méthodes permettent d'obtenir la charge d'un complexe, de faibles constantes de formation, des constantes de transmétallation, ainsi que la vitesse de relaxation électronique.