Proteomic analyses for a molecular characterization of animal glues.

Animal glues are widely used in restoration, serving as adhesives, binders, and consolidants for or-ganic and inorganic materials. Their variable performances are intrinsically linked to the adhesive properties of collagen, which determines the glue’s chemical, physical, and mechanical properties. We molecularly characterized by mass spectrometric techniques the protein component of a set of artificial and commercial glues. A shotgun proteomic analysis provided the animal origin, even when in mixture, and allowed to discriminate between hide and bone glue on the basis of the presence of collagen type III, which is absent in bone and present in connective skin/hide tissues. Chemical modifications which are expected to be affected by the actual preparation protocol from the original animal tissue were investigated. Deamidation, methionine oxidation and backbone cleavage were systematically analysed as main signatures of collagen modifications, demonstrating variability in the collagen modifications among the different glues.