Proteomics is a powerful tool for studying the proteins present in biological tissues. This method is attracting growing interest in forensic anthropology. Currently, the post-mortem interval is difficult to determine due to the complexity of biochemical processes during body decomposition, especially if the remains are only bones and teeth. In collaboration with the Forensic Taphonomy and Anatomy Unit of Lille university, we describe a minimally invasive high-resolution mass spectrometry method for identifying potential markers of this interval, from a cohort of 174 teeth from sites of forensic or archaeological interest with intervals ranging from 2020 to 4250-3800 BC. Enamel proteins were extracted by acid etching, digested by trypsin, purified, and analyzed by mass spectrometry. Data were mined with Maxquant, PEAKS and in house python program. Firstly, the identification of the sex of individuals was carried out using amelogenin peptides. The peptides are derived from a group of protein isoforms, amelogenin isoform X (AMELX) and amelogenin isoform Y (AMELY), which are respectively encoded by a gene located on the X and Y chromosomes. The ratio of intensities obtained by LC-MS/MS of the AMELX, and Y peptides was compared to determine sex. It should be noted that, AMELX is 4 times more represented than AMELY which requires statistical tests for degraded bones. Secondly, the analyses show that the percentage of deamidation increases with the age of the sites, i.e. as a function of the interval. Some peptides have a higher deamidation value than others for the same site, potentially due to the amino acid sequence or 3D conformation of the peptide in the protein. A blind statistical test showed a separation of the sites. This post-translational modification may be a marker of the post-mortem interval. Other modifications and degradation of peptides are being studied and an absolute quantification of proteins of interest in enamel will be carried out.