Molecular insights into tempera art: an approach to phosphorylated proteins profiling

The protein-based binders used in tempera painting techniques are complex natural matrices, typically from animal sources such as egg yolk or milk. These proteins exhibit numerous post-translational modifications (PTMs), particularly phosphorylation, which significantly influence their chemical and physical properties. The formation of three-dimensional networks through protein cross-linking underpins the creation of the pictorial layers. It is therefore reasonable to hypothesize a correlation between the stability of these layers and the structural properties of the constituent proteins. This study proposes an analytical methodology for the extraction and characterization of phosphoproteins. The procedure involves enrichment protocols and advanced biomolecular mass spectrometry techniques, initially optimized using pictorial specimens and subsequently applied to historical samples. The results demonstrate the potential for comprehensive characterization of the biomolecules under investigation, revealing considerable variability—particularly in historical samples, which are more susceptible to degradation and environmental exposure. The data are available through ProteomeXchange with the identifier PXD053038.