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 or no cleavage at arginyl-proline and lysyl-proline bonds.  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.
G-Biosciences' Mass Spectrometry Grade Trypsin (Figure 1) is a chemically methylated to yield an enzymatically active protein with maximum trypsin specificity and is extremely resistant 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. The resulting trypsin is extremely resistant to autolysis and has a specific activity over 10,000 units/mg protein.  The maximum activity is in the pH range of 7-9 and the activity is reversibly inactivated at pH 4.
Unlike other trypsin preparations, our Mass Spectrometry Grade Trypsin is highly stable (Figure 2), maintaining its activity in severe denaturing buffers (Figure 3) and as a result can be stored for a long period without any loss of activity (Figure 2).