Protease, S. aureus (Endoproteinase Glu C) (EC 3.4.21.19)

Endoproteinase-Glu-C Protease from S. aureus V8 specifically cleaves peptide bonds on the COOH-terminal side of either aspartic or glutamic acid. In the presence of ammonium buffers, the enzyme specificity is limited to glutamic sites. It has a molecular weight of 27,000 daltons and optimum pH's of 4.0 and 7.8 with hemoglobin as the substrate. It is is inhibited by diisopropylfluorophosphate and monovalent anions such as F-, Cl-, CH3COO- and NO3-. Enzyme activity is determined by the casein digestion assay described by Drapeau (Methods Enzymol., 45, 469, 1976). Activity: >500 units per mg dry weight, Absorbance (A280) at 1mg/ml: As reported, Unit Definition: One Unit causes a change of 0.001 absorbance unit (at 280nm) per minute at 37°C, pH 7.8 using casein as the substrate. , Extinction Coefficient: 4.26, Optimum pH: 4.0 and 7.8 with hemoglobin substrate, Inhibitors: Diisopropyl fluorophosphate (DFP) and monovalent anions such as F-, Cl-, Br-, CH3COO-, and NO3- , Quality Control: SDS-PAGE, Storage and Stability: Stable for 6 months after receipt at 4ºC. Autolysis occurs at temperatures greater than 40ºC. The enzyme is fully active in 2mg/ml SDS