Proteases for Mass Spectrometry

Trypsin, the most widely used protease in mass spectrometry analysis, utilizes its high specificity to cleave proteins, resulting in peptides with a strong C-terminal charge. Trypsin is a serine protease that specifically cleaves at the carboxylic side of lysine and arginine residues. Lysine residues in the porcine trypsin have been modified by reductive methylation, yielding a highly active and stable molecule that is extremely resistant to autolytic digestion. The specificity of the purified trypsin is further improved by TPCK treatment, which inactivates chymotrypsin.

When working with tightly folded proteins, the...

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Trypsin, the most widely used protease in mass spectrometry analysis, utilizes its high specificity to cleave proteins, resulting in peptides with a strong C-terminal charge. Trypsin is a serine protease that specifically cleaves at the carboxylic side of lysine and arginine residues. Lysine residues in the porcine trypsin have been modified by reductive methylation, yielding a highly active and stable molecule that is extremely resistant to autolytic digestion. The specificity of the purified trypsin is further improved by TPCK treatment, which inactivates chymotrypsin.

When working with tightly folded proteins, these proteins can resist trypsin digestion, resulting in an inadequate distribution of trypsin cleavage sites that can generate peptides that are either too long or too short. In addition, post-translation modifications (PTMs) present yet another challenge because glycans often limit trypsin access to cleavage sites, whereas acetylation or di- and trimethylation of lysine and arginine residues make them resistant to trypsin digestion. Promega offers several alternative proteases and a unique surfactant that can complement standard tryptic digestions to provide enhanced data.

For additional details see a specific protease catalog page.

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