title: Identification of proteins in renaissance paintings by proteomics.
abstract: The presented work proposes a new methodology based on proteomics techniques to identify proteins in old art paintings. The main challenging tasks of this work were (i) to find appropriate conditions for extracting proteins from the binding media without protein hydrolysis in amino acids and (ii) to develop analytical methods adapted to the small sample quantity available. Starting from microsamples of painting models (ovalbumin-based, which is the major egg white protein, and egg-based paintings), multiple extraction solutions (HCl, HCOOH, NH3, NaOH) and conditions (ultrasonic bath, mortar and pestle, grinding resin) were evaluated. The best results were obtained using a commercial kit including a synthetic resin, mortar and pestle to grind the sample in an aqueous solution acidified with trifluoroacetic acid at 1% with additional multiple steps of ultrasonic baths. The resulting supernatant was analyzed by MALDI-TOF in linear mode to verify the efficiency of the extraction solution. An enzymatic hydrolysis step was also performed for protein identification; the peptide mixture was analyzed by nanoLC/nanoESI/Q-q-TOF MS/MS with an adapted chromatographic run for the low sample quantity. Finally, the developed methodology was successfully applied to Renaissance art painting microsamples of approximately 10 microg from Benedetto Bonfigli's triptych, The Virgin and Child, St. John the Baptist, St. Sebastian (XVth century), and Niccolo di Pietro Gerini's painting, The Virgin and Child (XIVth century), identifying, for the first time and without ambiguity, the presence of whole egg proteins (egg yolk and egg white) in a painting binder.
authors.affiliation: Chimie Organique et Macromoléculaire, UMR CNRS 8009, and Protéomique, Modifications Post-traductionnelles et Glycobiologie, IFR 118, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Tokarski
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Martin
authors.forename: Christian
authors.initials: C
authors.lastname: Rolando
authors.forename: Cécile
authors.initials: C
authors.lastname: Cren-Olivé
mesh_terms: D004527:Egg Proteins / Q000032:analysis; D049668:History, 15th Century; D049691:History, Medieval; D010151:Paintings / Q000266:history; D011506:Proteins / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004527:Egg Proteins; D011506:Proteins