Table 1. Confidently Identified sY-Peptides from the HEK293 Cellular Secretome^a.

^aDetailed are the accession number, gene name, protein description, peptide sequence, −log₁₀P score, Δppm from theoretical m/z, the observed m/z, charge state (z), and identified PTMs as determined by the search engine (1% FDR). Listed is a concatenated version of all modified peptide identifications (all peptides having been identified in at least two separate experiments, with multiple PSMs per experiment), maintaining only the highest −log₁₀P score peptide for a unique sY-site. The predicted (acidic) sY-site is highlighted. Cm—carbamidomethylation. All predicted sY sites were searched for prior annotation as being either phosphorylated or sulfated in UniProt and the PhosphositePlus (PSP) database [accessed July 2023]; HTP—details of the number of times of phosphorylation were reported in PSP in a high throughput study.