TAILS is a novel multiplex quantitative proteomics platform for the determination of N-terminomes and the system-wide identification of protease substrates and cleavage sites in complex biological samples. In this method, all natural and cleaved N-termini and lysines in a proteome (exposed or not exposed to a protease) are blocked by differential isotopic labeling. Pooled samples are trypsinized and then, to reduce sample complexity, incubated with an aldehyde-derivatized amine-reactive polymer that removes all unlabeled peptides. TAILS therefore focuses on the proteomic analysis of N-termini of all proteins, which together form the N-terminome.
Protease-generated neo-N-termini are only present in the protease-exposed but not in the control sample and are characterized by a high ratio in relative quantification of corresponding isotopic labels. Thereby, the use of isobaric tags for relative and absolute quantitation (iTRAQ) allows the analysis of up to eight samples in a single experiment.
See also: TAILS@wikipedia!!!