Serum free condition media were collected from 24 h ARPE-19 cell cultures. The protein content in these media were concentrated and separated by SDS–PAGE. Gel bands where excised, digested with trypsin and the resulting peptides analyzed by LC-MS/MS as described in the method. UniProt ID column shows accession number for each identified protein. Peptide count column shows the number of tryptic peptides detected and identified for each protein. The last column indicates the subcellular localization of each protein. Each of these proteins were identified by at least two peptides and validated by detection of both labeled and unlabeled peptide pairs. To access the data, click or select the words “Appendix 1.” This will initiate the download of a compressed (pdf) archive that contains the file.