Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

Fructosamines are formed from glucose and primary amines in s spontaneous, two step reaction. When this reaction involves amino-groups of proteins, it is termed “protein glycation”. The formation of fructosamines is a slow and nearly irreversible process. Two enzymes, fructosamines-3-kinase (FN3K) and fructosamines-3-kinase related protein (FN3K-RP), responsible fir the removal of ketosamines from proteins in a process called “declygation”, have recently been described. These osamines-3-kinase catalyze with a high affinity the phosphorylation of protein-boundosamines on the third carbon of their deoxyfrutose moiety. The osamines-3-phosphate formed in this way are unstable and spontaneously decompose into inorganic phosphate and 3-deoxuglucosome, with concomitant regeneration of the unglycated amine.
To study the physiological function of fructosamine-3-kinase, we firstly tested the hypothesis that glycated proteins would be degraded by the proteasome, in preference to unglycated proteins. For this purpose, we set up a cellular model of hepatocytes in culture from mice with or without FN3K. At first, we checked that FN3K was expressed several days in these cells. Then, we determined the glycation extent of cytosolic enzymes in FN3K+/+ or FN3K-/- hepatocytes incubated with different concentrations of glucose, with or without inhibitor of proteasome. The results obtained do not support the idea that the proteasome degrades glycated proteins preferentially to unglycated proteins.
Secondly, we studied a cytosolic enzyme, O-N-acetylglucosaminidase, which cleaves O-N-acetylglocusamine residues off certain cytosolic and nuclear proteins, to know if two cellular processes, the transport of glucose by Glut 1 in erythtocytes and apoptosis on hepatocytes. Our results do not indicate that fructosamines affect significantly these processes La glycation est un processus spontané dans lequel les sucres réagissent avec des amines (libres ou liées au protéines) menant à la formation quasi irréversible de composés appelés « osamines » (fructosamines lorsque le sucre et la glucose). On sait depuis peu que les résidus osamines peuvent être enlevés des protéines par un processus de « déglycation » amorcé par deux enzymes, la fructosamines-3-kinase (FN3K) et la fructosamine-3-kinase related protein (FN3K-RP). Ces osamines—kinases phosphorylent en effet avec une haute affinité les résidus osamines liés aux protéines sur le troisième carbone de leur partie glucidique. Les osamines-3-phosphates ainsi formées sont instables, et se décomposent spontanément en régénérant l’amine initiale. L’intervention in vivo des osamines-3-kinases dans la déglycation a été démontrée pour l’hémoglobine dans les érythrocytes humains.
Afin d’appréhender le rôle physiologique de la déglycation des protéines, nous avons tout d’abord voulu tester l’hypothèse selon laquelle les protéines glyquées se feraient davantage dégrader par le protéasome que les protéines non glyquées. Pour tester cela, nous avons mis au point un modèle d’hépatocytes de souris en culture provenant d’animaux contrôles ou déficients en FN3K. Nous avons tout d’abord vérifié que la FN3K restait exprimée pendant plusieurs jours dans ces cellules. Nous avons alors mesuré l’état de glycation d’enzymes cytosoliques dans es hépatocytes FN3K+/+ ou FN3K-/- incubés en présence de différentes concentrations de glucose, avec ou sans un inhibiteur du protéasome. Les données obtenues plaident contre l’idée que le protéasome dégraderait préférentiellement les protéines porteuses du fructosamines qui auraient échappé à l’action de la FN3K.
La deuxième hypothèse que nous avons testée est celle que les fructosamines agiraient comme inhibiteur d’une enzyme cytosolique, la O-N-acétylglucosaminidase, qui enlève les résidus N-acétylglucosamine fixés sur certaines protéines cytosoliques et nucléaires. Nous avons également testé l’effet d’une déficience en FN3K sur deux processus cellulaires, le transport de glucose par Glut 1 et le phénomène d’apoptose. Les résultats obtenus ne semblent pas indiquer que la présence de fructosamines affecte significativement ces trois processus

Protein Renaturation --- FN3KRP protein, human --- Hepatocyte Nuclear Factor 5 --- Mice

Choose an application

• Reference Manager
• EndNote
• RefWorks (Direct export to RefWorks)

This Special Issue entitled “Environmental Restoration of Metal-Contaminated Soils” focuses on the issues linked to soils contaminated with heavy metals and metalloids, dealing with current research activities around the world at the laboratory and field scale. These activities are the pillars for the application of strategies on a real-world scale, to remediate industrial soils affected by the problem. When an industrial soil contains pollutants, the main problem is the removal of these compounds. However, other features are present, linked to the health of the population living in its proximity. This Special Issue reports experimental run findings with the aim of removing heavy metals and/or metalloids from soil, making use of challenging techniques, and also demonstrating approaches for the assessment of the risks to human health.

Research & information: general --- seedling biomass --- heavy metals --- soil amelioration --- urban gardens --- pollution --- contaminated soil --- amendment --- edible plants --- metal --- citric acid --- EDTA --- electrokinetic remediation --- bioaccessibility --- bioavailability --- metals --- contaminated sites --- risk assessment --- natural sorbents --- ameliorants --- disturbed lands --- adsorption --- recultivation --- environmental remediation --- revitalization --- renaturation --- restoration --- rehabilitation --- reclamation --- heavy metals and metalloids --- removal techniques --- hydrophobic --- copper --- microfluidics --- pH change --- remediation --- seedling biomass --- heavy metals --- soil amelioration --- urban gardens --- pollution --- contaminated soil --- amendment --- edible plants --- metal --- citric acid --- EDTA --- electrokinetic remediation --- bioaccessibility --- bioavailability --- metals --- contaminated sites --- risk assessment --- natural sorbents --- ameliorants --- disturbed lands --- adsorption --- recultivation --- environmental remediation --- revitalization --- renaturation --- restoration --- rehabilitation --- reclamation --- heavy metals and metalloids --- removal techniques --- hydrophobic --- copper --- microfluidics --- pH change --- remediation