Systematic Evaluation of Advantages of Lys-C/trypsin Sequential Digestion in Proteomics Sample

Endoproteinase lysine-C (Lys-C)/trypsin sequential digestion and trypsin digestion were used in 293T cell proteomics sample preparation and the differences of Lys-C/trypsin sequential digestion and trypsin digestion in proteomics sample preparation were systematically evaluated. It was found that the number of identified peptides and proteins increased significantly and missed cleavage sites, especially K sites decreased dramatically through Lys-C/trypsin sequential digestion. The average sequence coverage of identified proteins in Lys-C/trypsin sequential digestion sample was higher than that in trypsin digestion sample. Besides, different amounts of enzymes were tested to select the optimal usage of enzymes in Lys-C/trypsin sequential digestion. This study provided the references for proteomics sample preparation.