Treatment of trypsin with phenylmethylsulfonyl fluoride (PMSF) followed by a strong base leads to the conversion of Serine 195 to dehydroalanine at the active site (1). Alpha and beta forms of anhydrotrypsin are separated by immobilized soybean trypsin inhibitor. The activity of anhydrotrypsin is greatly reduced compared to native trypsin as quantified by chromogenic substrate (2). Anhydrotrypsin provided by our company is the single chain beta-form prepared from Type XIII bovine trypsin.
1. Ako, H. et al. (1972) Biochem Biophys Res Commun. 47:1402-1407.
2. Olson, S.T. et al. (1995) J. Biol. Chem. 270:30007-30017.