Abstract: 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 micro-reactor 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.

Key words: Nano liter micro reactor, Capillary immobilized enzyme, MALDI TOF MS, Peptide mapping analysis