A cyclic-olefin-copolymer microfluidic immobilized-enzyme reactor for rapid digestion of proteins from dried blood spots

作者：Wouters Bert^*; Dapic Irena; Valkenburg Thalassa S E; Wouters Sam; Niezen Leon; Eeltink Sebastiaan; Corthals Garry L; Schoenmakers Peter J

来源：Journal of Chromatography A, 2017, 1491: 36-42.

DOI：10.1016/j.chroma.2017.01.078

• Proteome
• Digestion
• Trypsin
• Polymer monolith
• Mass spectrometry
• Bottom-up

A critical step in the bottom-up characterization of proteomes is the conversion of proteins to peptides, by means of endoprotease digestion. Nowadays this method typically uses overnight digestion and as such represents a considerable bottleneck for high-throughput analysis. This report describes protein digestion using an immobilized-enzyme reactor (IMER), which enables accelerated digestion times that are completed within seconds to minutes. For rapid digestion to occur, a cyclic-olefin-copolymer microfluidic reactor was constructed containing trypsin immobilized on a polymer monolithic material through a 2-vinyl-4,4-dimethylazlactone linker. The IMER was applied for the rapid offline digestion of both singular protein standards and a complex protein mixture prior to liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS) analysis. The effects of protein concentration and residence time in the IMER were assessed for protein standards of varying molecular weight between 11 and 240 kDa. Compared to traditional in-solution digestion, IMER-facilitated protein digestion at room temperature for 5 min yielded similar results in terms of sequence coverage and number of identified peptides. Good repeatability was demonstrated with a relative standard deviation of 6% for protein sequence coverage. The potential of the IMER was also demonstrated for a complex protein mixture in the analysis of dried blood spots. Compared to a traditional workflow a similar number of proteins could be identified, while reducing the total analysis time from 22.5 h to 4h and importantly omitting the sample-pre-treatment steps (denaturation, reduction, and alkylation). The identified proteins from two workflows showed similar distributions in terms of molecular weight and hydrophobic character.

• 出版日期2017-3-31