Integrated microanalytical technology enabling rapid and automated proteinidentification

Protein identification through peptide mass mapping by matrix-assisted lase r desorption/ionization time-of-night mass spectrometry (MALDI-TOF MS) has become a standard technique, used in many laboratories around the world. Th e traditional methodology often includes long incubations (6-24 h) and exte nsive manual steps. In an effort to address this, an integrated microanalyt ical platform has been developed for automated identification of proteins. The silicon micromachined analytical tools, i.e. the microchip immobilized enzyme reactor (mu-chip IMER), the piezoelectric microdispenser, and the hi gh-density nanovial target plates, are the cornerstones in the system. The mu-chip IMER provides on-line enzymatic digestion of protein samples (1 mu L) within 1-3 min, and the microdispenser enables subsequent on-line picoli ter sample preparation in a high-density format. Interfaced to automated MA LDI-TOF MS, these tools compose a highly efficient platform that can analyz e 100 protein samples in 3.5 h, Kinetic studies on the microreactors are re ported as well as the operation of this microanalytical platform for protei n identification, wherein lysozyme, myoglobin, ribonuclease A, and cytochro me c have been identified with a high sequence coverage (50-100%).