These Sequencing Grade endoproteinases are highly purified proteinases that are modified chemically in order to reduce autolysis and thereby increase the enzyme stability over an extended period. Use of modified endoproteinases results in greater control of protein fragmentation reactions due to consistent enzymatic activity over long digestion periods.
Endoproteinase Asp-N is a metallo enzyme isolated from a mutant of Pseudomonas fragi. The enzyme specifically hydrolyzes peptide bonds on the N-terminal side of aspartic and cysteic acids. Its optimum activity is at pH's 6.5-8.0. The enzyme has a molecular weight of 27 kD.
Asp-N endoproteinase is subjected to extensive purification to remove contaminating proteases which could affect the specificity of the digestion process. The highly purified enzyme is subsequently modified chemically by a process developed at Princeton Separations. As a result, the modified enzyme is more resistant to autolysis and has improved stability. The modified enzyme retains at least 80% to 90% of its activity after six hours incubation in digestion buffer, and 65% to 75% of its activity after 24 hours incubation under the same conditions.
