Digestif comprises a soluble recombinant protein scaffold + 11 artificial peptides (iRT) with good ionization
Amino acids flanking iRT cleavage site either favour or hinder protease cleavage.
Retention time & relative intensity pattern of released iRT can assess the quality of sample workup, the extent of digestion, LC-MS performance & inter/intra-lab variability
Reference: DIGESTIF: A Universal Quality Standard for the Control of Bottom-Up Proteomics Experiments. J Proteome Res. 2015 Feb 6;14(2):787-803