An enzymatic microreactor with a volume of 470 nL has been prepared by immobilizing trypsin on a 10 cm long reactive porous polymer monolith located in a 100 μm i.d. fused silica capillary. This reactor affords suitable degrees of digestion of proteins even after very short residence times of less than 1 min. The performance is demonstrated with the digestion of eight proteins ranging in molecular mass from 2848 to 77 754. The digests were analyzed using mass spectrometry in two modes: off-line MALDI and in-line nanoelectrospray ionization. The large numbers of identified peptides enable a high degree of sequence coverage and positive identification of the proteins. The extent of sequence coverage decreases as the molecular mass of the digested protein increases.
- High-throughput protein identification
- Immobilized enzyme
- Mass spectrometry
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