Before revision:  Peptide mass spectrometry is a powerful tool for detecting cellular expression of proteins and therefore is an attractive approach for verifying the protein coding potential of genes. However, a range of technical difficulties limit the coverage from proteomics experiments, with the highest recorded coverage of the human proteome being approximately 50\% of human genes .
After revision:  Peptide mass spectrometry is a powerful tool for detecting cellular expression of proteins and therefore is an attractive approach for verifying the protein coding potential is the detection of cellular protein expression through peptide mass spectrometry experiments .