Carboxylate-imidazole cooperativity in dipeptide-functionalized gold nanoparticles with esterase-like activity.
We report here the first example of peptide-functionalized gold nanoparticles hydrolytically active against carboxylate esters. The active units are constituted by His-Phe-OH terminating thiols. The confinement of the catalytic units in the monolayer covering the nanoparticles triggers a cooperative hydrolytic mechanism operative at pH < 7 in which a carboxylate and an imidazolium ion act as general base and general acid, respectively. Such a mechanism is absent with an analogous monomeric dipeptide, and this results in a more than 300-fold rate acceleration of the hydrolytic process at low pH in the presence of the functional nanoparticles.
Pengo
Paolo
P
University of Padua, Department of Chemical Sciences and ITM-CNR, Padua Section, 35131 Padua, Italy.
Polizzi
Stefano
S
Pasquato
Lucia
L
Scrimin
Paolo
P
D002087:Butyrates / Q000737:chemistry*; D004136:Dinitrobenzenes / Q000737:chemistry; D004151:Dipeptides / Q000737:chemistry*; D004950:Esterases / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D007700:Kinetics; D007930:Leucine / Q000031:analogs & derivatives; D049329:Nanostructures / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry
D002087:Butyrates; D004136:Dinitrobenzenes; D004151:Dipeptides; D007093:Imidazoles; D013438:Sulfhydryl Compounds; D006046:Gold; D004950:Esterases; D007930:Leucine