Miniaturisation of trypsin immobilised enzymatic reactor for protein digestion

Miniaturised immobilised enzymatic reactors can be used for small scale digestion of proteins. There is need for such devices; small scale devices are used either for processing of analytical sample quantities, or as proof of concept before protein digestion at larger scale. This application note compares the performance of a flow through miniaturised immobilised enzymatic reactor (μIMER) with in-solution batch digestion of simple proteins and complex matrices. Automation of peptide analysis by coupled LC-MS is explored as an option to increase throughput. In the cases evaluated, the miniaturised immobilised enzymatic reactor offered comparative results to overnight in-solution digestion, within less than 10 minutes.

Pre-activated CIMmic™ monolithic columns with 100 μL bed volume were immobilised with trypsin from bovine pancreas. This small format allows coupling to HPLC for on-line protein digestion, as well as syringe (manual) operation of the IMER. Pre-treated samples (denatured, alkylated and ultra-filtered) are injected into the column, and the eluate (tryptic digests) are subjected to LC-ESI-MS-MS analysis for protein identification and post-translational modification (PTM) determination.