RT Journal Article SR Electronic T1 DirectMS1: MS/MS-free identification of 1000 proteins of cellular proteomes in 5 minutes JF bioRxiv FD Cold Spring Harbor Laboratory SP 756213 DO 10.1101/756213 A1 Mark V. Ivanov A1 Julia A. Bubis A1 Vladimir Gorshkov A1 Irina A. Tarasova A1 Lev I. Levitsky A1 Anna A. Lobas A1 Elizaveta M. Solovyeva A1 Marina L. Pridatchenko A1 Frank Kjeldsen A1 Mikhail V. Gorshkov YR 2019 UL http://biorxiv.org/content/early/2019/09/05/756213.abstract AB Proteome characterization relies heavily on tandem mass spectrometry (MS/MS) and is thus associated with instrumentation complexity, lengthy analysis time, and limited duty-cycle. It was always tempting to implement approaches which do not require MS/MS, yet, they were constantly failing in achieving meaningful depth of quantitative proteome coverage within short experimental times, which is particular important for clinical or biomarker discovery applications. Here, we report on the first successful attempt to develop a truly MS/MS-free and label-free method for bottom-up proteomics. We demonstrate identification of 1000 protein groups for a standard HeLa cell line digest using 5-minute LC gradients. The amount of loaded sample was varied in a range from 1 ng to 500 ng, and the method demonstrated 10-fold higher sensitivity compared with the standard MS/MS-based approach. Due to significantly higher sequence coverage obtained by the developed method, it outperforms all popular MS/MS-based label-free quantitation approaches.