39 research outputs found
GuHCl induced Unfolding-Folding transition of a hinge-bending protein: Horse Muscle Phosphoglycerate kinase
Role of ProteinâSolvent Interactions in Refolding: Effects of Cosolvent Additives on the Renaturation of Porcine Pancreatic Elastase at Various pHs
The effects of curcumin, mangiferin, resveratrol and other natural plant products on aminopeptidase B activity
International audienceAminopeptidase B (Ap-B) is a Zn2+-aminopeptidase of the M1 family which is implicated, in conjunction with the nardilysin endoprotease, in the generation of miniglucagon, a peptide involved in the maintenance of glucose homeostasis. Other in vivo physiological roles have been established for this vertebrate enzyme, such as the processing of Arg-extended forms of human insulin and cholecystokinin 9 and the degradation of viral epitopes in the cytoplasm. Among M1 family members, Ap-B is phylogenetically close to leukotriene A4 hydrolase (LTA4H), a bi-functional aminopeptidase also able to transform LTA4 in LTB4 (a lipid mediator of inflammation). As the activities of LTA4H are reported to be inhibited by resveratrol, a polyphenolic molecule from red wine, the effect of this molecule was investigated on the Ap-B activity. Several other active phenolic compounds produced in plants were also tested. Among them, curcumin and mangiferin are the most effective inhibitors. Dixon analysis indicates that curcumin is a non-competitive inhibitor with a Ki value of 46âŻÎŒmol.Lâ1. Dixon and Lineweaver-Burk representations with mangiferin show a mixed non-competitive inhibition with Kiâ and Ki values of 194âŻÎŒmol.Lâ1 and 105âŻÎŒmol.Lâ1, respectively. At 200âŻÎŒmol.Lâ1, no significant effect was observed with caffeic, chlorogenic, ferulic, salicylic and sinapic acids as well as with resveratrol. Analyses on the 3D-structure of LTA4H with resveratrol (pdb: 3FTS) and the Ap-B 3D-model allow hypothesis to explain theses results