Trypsin is a serine endopeptidase that specifically cleaves peptide bonds on the carboxy side of s-aminoethyl cysteine, arginine and lysine residues, and typically, there is little to no cleavage at arginyl-proline and lysyl-proline bonds

G-Biosciences' Mass Spectrometry Grade Trypsin is chemically methylated to yield an enzymatically active protein with maximum trypsin specificity and extreme resistance to autolysis. In addition, the modified trypsin is TPCK treated to inactive the interfering chymotrypsin activity, and the resulting protein is affinity purified and lyophilized to produce our Mass Spectrometry Grade Trypsin.The resulting trypsin has a specific activity over 10,000 units per milligram protein. The maximum activity is in the pH range of 7 to 9 and activity is reversibly inactivated at a pH of 4.Unlike other trypsin preparations, our Mass Spectrometry Grade Trypsin is highly stable. As a result, it can be stored for a long period of time without any loss of activity.

The distribution of these residues in proteins allows trypsin digestion to produce peptides that are readily identified by mass spectrometry. Native trypsin is prone to autolysis that results in pseudotrypsin, which exhibits a broader proteolytic specificity (a chymotrypsin-like activity) and trypsin fragments that interfere with sequence analysis.