Examples of proteolytic processing identified by TAILS in stored platelets. Platelets were stored under blood-banking conditions for 9 days with or without EDTA-free cOmplete protease inhibitor cocktail, and the platelet proteome from different days was characterized by 4-plex iTRAQ TAILS (day 2, day 4, day 4 + inhibitors, day 9). Examples of the identified N termini are shown for tropomyosin-4 (A), l-lactate dehydrogenase A (B), and TCP-1β (C). Peptides identified by TAILS are underlined within the respective protein sequences; sequence positions of internal neo- and natural N termini are indicated by arrows. Start and end position of the identified peptides and their N-terminal modifications, sequences, preceding amino acids, and iTRAQ ratios are shown. Ac denotes N-terminal acetylation.