EC 3.4.21.36
SOURCE. Porcine pancreas.
SPECIFICATIONS. Chromatographically purified, salt-free, lyophilized, water soluble powder.
MW= 25,500.
Store at 5°C. Stable 9-12 months with no decrease in activity.
115-125 units per mg of protein on the substrate elastin-orcein. One unit will solubilized 1 mg of elastin in 20 minutes at pH 8.8 and 37°C (11). Assay procedure is described in Methods. Free of trypsin, chymotrypsin, lipase, alpha-amylase and the carboxypeptidases. Greater than 9 units per mg of protein on the substrate Suc-Ala-Ala-Ala-pNA. One unit will hydrolyze 1 µmole per minute at pH 8.3 and 25°C. Assay described in Methods.
PREPARATION.
High purity elastase is isolated from 2X crystallized elastase (Product No. E134). The 2X elastase is chromatographed on DEAE-cellulose at pH 8.8 to remove anionic non-specific protein. The elastolytic effluent is chromatographed at pH 5.0 on CM-cellulose recovering the highest specific activity by elution with salt gradient. Trace trypsin, and chymotrypsin contamination is removed by affinity chromatography.
PURITY.
The high purity elastase is homogenous on 15% polyacrylamide electrophoresis at pH 4.5 and on gel exclusion chromatography (G200) at pH 5.0 and 25°C.
FREE OF TRYPSIN; trypsin not detected on 0.5 mg elastase after more than 24 hour incubation at 25°C on the substrate N-benzoyl-DL-arginine-pNA (BAPNA).
FREE OF ALPHA-CHYMOTRYPSIN; alpha-chymotrypsin not detected on 0.5 mg elastase after more than 24 hr. incubation at 25°C on the substrate N-benzoyl-L-tryosine ethyl ester (BTEE).