Age estimation of museum wool textiles from Ovis aries using deamidation rates utilizing matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Cultural heritage contains a large number of precious proteinaceous specimens, such as wool and silk textiles, leather objects, paper, paint, coatings, binders (and associated adhesives), etc. To minimize the degradation of and to preserve these artifacts, it is desirable to understand the fundamental factors that cause their degradation, to identify the deterioration markers that determine their degradation stage and their age, and to use technologies that can provide this information rapidly while consuming a minimal amount of sample. There are several forces that cause protein degradation, including amino acid racemization, protein deamidation, and protein truncation. The purpose of this paper is to study protein deamidation using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for high-throughput dating of museums wool specimens. For proof of concept, several well-dated sheep's wool textiles from museum collections were analyzed. For wool samples aged from the present to ~400 years ago, the deamidation of two asparagine-containing peptides obtained from the tryptic digest of sheep wool were found to behave linearly in time, indicating that they could act as a potential biomarker of aging for wool samples.