GingisREX: A Complementary Enzyme for the Detection of Bacterial Proteins.

Reliable enzymatic digestion underscores successful mass-spectrometry-based proteomics experiments. In this study, we compare the use of the arginine-specific protease, GingisREX, against a more traditional approach in the identification of Escherichia coli proteins. An increased number of protein identifications were noted when GingisREX was used compared to a trypsin/lys-C mixture. This improvement was attributed to the generation of fewer peptides per protein, resulting in a simpler peptide mixture. Furthermore, GingisREX exhibited increased digestion efficiency, fewer missed cleavages, and improved MS/MS data quality for higher molecular weight peptides. The data here establish GingisREX to be a protease complementary to trypsin for enhanced detection of bacterial proteins. With further optimization, GingisREX could prove to be an effective alternative to trypsin for identifying host cell proteins in biotherapeutics.