I am not sure I understand the question. Do you want a database of peptides identified by mass spectrometry ? If so, have a look at PeptideAtlas or Proteomics DB. Pride is a proteomics data repositories and you will also find peptides in the data sets but you'll need to access them using project accession. Or do you want to do peptide identification from your mass spectrometry data ? If so, have a look at this post.