Studies on rapid micro-scale peptide mapping analysis using a capillary micro-reactor

Peptide mapping analysis by combining the enzymatic digestion and the MALDI-TOF-MS has emerged as a powerful tool for identification and characterization of protein. We describe a nanoliter microreactor prepared with immobilization of enzyme on the porous wall of a capillary. The advantages of the prepared micro-reactor for digestion of the proteins are the elimination of enzyme autolysis and concentration of the micro-sample. Horse heart cytochrome c is selected as the target protein for the evaluation of micro-reactor, and it is found that about 0.1 picomole of protein analyte could routinely be digested for peptide mapping analysis and even femtomole of protein can be well characterized