Chymotryptic proteolysis accelerated by alternating current for MALDI-TOF-MS peptide mapping

Alternating current (AC) has been employed to enhance the efficiency of chymotryptic proteolysis for peptide mapping. It was allowed to flow through the mixture solution of proteins and chymotrypsin via a pair of platinum wire electrodes. Bovine serum albumin (BSA) and cytochrome c (Cyt-c) were digested by the novel proteolysis approach to demonstrate its feasibility and performance. The results indicated that AC significantly accelerated in-solution chymotryptic proteolysis and the digestion time was substantially reduced to 5 min. The digests were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with sequence coverages of 46% (BSA) and 90% (Cyt-c) that were much better than those obtained by using 12-h conventional in-solution chymotryptic proteolysis. In addition, AC-assisted chymotryptic proteolysis was employed to digest human serum to demonstrate its suitability to complex protein sample. The present proteolysis strategy is simple and efficient and will find a wide range of applications in proteomic research.