DIFFUSION OF TRANSITION ADATOMS ON PERFECT AND STEPPED TRANSITION METAL SURFACES FROM BINDING ENERGY CALCULATIONS

Nous calculons les lignes de niveaux de l'énergie de liaison d'un adatome de la série de transition 5d sur la surface avec marches [m(110) x (0[MATH]1)] du tungstène. Nous en déduisons les chemins de diffusion et les énergies d'activation correspondantes extrapolées à O K. Ces résultats sont comparés à ceux obtenus sur une surface parfaite (110) et sont en assez bon accord avec les expériences de FIM.We calculate the binding energy contour maps for a single adatom of the 5d transition series on a stepped [m(110) x (0-11)]W surface from which the diffusion channels and corresponding activation energies are deduced. These results are compared to those obtained for a perfect (110) surface and are in rather good agreement with FIM experiments

Gastrointestinal digestion enhances the endothelium-dependent vasodilation of a whey hydrolysate in rat aortic rings

International audienceWhey proteins present encrypted biofunctional peptides that need to be released from the native protein to exert their biological activity. Antihypertensive whey peptides are the most studied ones, which can be explained by high prevalence of this chronic degenerative disease. The present study investigated whether the molecular changes occurred during the gastrointestinal digestion of a whey protein hydrolysate could modulate its va-sorelaxant potential in rat aortic rings. Spectrophotometric data and SDS-PAGE gel showed a small degree of hydrolysis during the gastric phase and intense intestinal proteolysis. RP-HPLC revealed the formation of a large peptide profile. During the simulated digestion, 198 peptides were generated and identified and, left-shifted the concentration-response curve of the endothelium-dependent vasorelaxation, as recorded for the digested hy-drolysates. In conclusion, gastrointestinal digestion of the whey hydrolysate leads to the generation of bioactive peptides with enhanced vasodilatory potency, reinforcing the relevance of whey-derived products in blood pressure regulation