This study presents a comparative analysis of three LysC endopeptidase homologues from Achromobacter lyticus (A. lyticus),Pseudomonas aeruginosa and Lysobacter enzymogenes for mass spectrometry-based proteomics. Utilizing a protein aggregation capture workflow with HeLa cell lysates, we assessed the enzymes’ cleavage specificity, digestion efficiency, and performance across various experimental conditions. Results showed that while all three LysC homologues exhibited high cleavage specificity at lysine residues, A. lyticus LysC outperformed the two others with superior peptide identification, digestion efficiency, and protein coverage, especially at shorter digestion times. Our experiments using a combination ofA. lyticusLysC and trypsin demonstrated the importance of employing LysC for significantly minimizing missed cleavage rates in tryptic digests, especially with regard to lysine-containing peptides. This study underscores A. lyticus LysC’s potential as an optimal choice for enhancing mass spectrometry-based proteomics.

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High-throughput proteomics is critical for understanding biological processes, enabling large-scale studies such as biomarker discovery and systems biology. However, current mass spectrometry technolo...

High-throughput mass spectrometry-based proteomics has gained increasing interest for both academic and industrial applications. As implementation of faster gradients has facilitated higher sample thr...

imageimageProteomics profiling of a pre-metastatic colorectal cancer cohort identifies four proteomics-based subtypes and highlights the role of CAVIN1 in relapse in EMT-like tumors. Mass-spectrometr...

High-grade serous ovarian carcinoma (HGSOC) is the deadliest gynecologic cancer. Key to the progression and ultimate lethality of this subtype is the intra-tumoral heterogeneity (ITH), which is define...

The SC-pSILAC method enables single-cell measurement of both protein abundance and turnover, providing notable advances in the depth and versatility of proteomic technologies.

Mass spectrometry-based single-cell proteomics (SCP) is gaining momentum but remains limited to a few laboratories due to the high costs and specialized expertise required. The ability to send samples to specialized core facilities would benefit nonspecialist laboratories and popularize SCP for biological applications. However, no methods have been tested in SCP to “freeze” the proteome state while maintaining cell integrity for transfer between laboratories or prolonged sorting using fluorescence-activated cell sorting (FACS). This study evaluates whether short-term formaldehyde (FA) fixation can maintain the cell states. We demonstrate that short-term FA fixation does not substantially affect protein recovery, even without heating and strong detergents, and maintains analytical depth compared with classical workflows. Fixation also preserves drug-induced specific perturbations of the protein abundance during cell sorting and sample preparation for SCP analysis. Our findings suggest that FA fixation can facilitate SCP by enabling sample shipping and prolonged sorting, potentially democratizing access to SCP technology and expanding its application in biological research, thereby accelerating discoveries in cell biology and personalized medicine.

Chip-Tip is a label-free quantification-based single-cell proteomics workflow for deep single-cell proteomics, which identifies over 5,000 proteins and 40,000 peptides in single HeLa cells.