Trypsin/Lys-C complex protease (MS grade) combines two recombinant proteases, Trypsin and Lys-C, to efficiently hydrolyze peptide bonds. Trypsin specifically cleaves at the C-terminal of arginine (R) and lysine (K), while Lys-C targets the C-terminal of lysine (K). This combination overcomes issues of missed cleavages due to Trypsin's slower digestion at lysine and arginine, PTM alterations on lysine, or hydrophobic C-termini like proline. It is suitable for digesting complex protein samples that are difficult to process enzymatically. This protease is used for protein characterization, single-cell omics, and large-cohort proteomics studies.