Purification and Characterization of Chymotrypsin-like Proteinase from Euphausia superba

Abstract

Proteinase A₂, a chymotrypsin type enzyme, was purified about 280-fold from an extract of Euphausia superba by DEAE-cellulose column chromatography, gel filtration on Sephadex G-75, and hydroxyapatite column chromatography. The final preparation was electrophoretically homogeneous. The molecular weight was 29, 000. The optimum pH was 8.0 and the optimum temperature was 45°C.
Proteinase A₂ hydrolyzed casein but not benzoyl-DL-arginine-p-nitroanilide, unlike other serine proteinases from antarctic krill.¹⁾ This enzyme was inhibited by DFP, PMSF, soybean trypsin inhibitor, but not TLCK, leupeptin, or antipain. Proteinase A₂ could hydrolyze benzoyl-tyrosineethylester and was inhibited by chymostatin.
These results suggest that proteinase A₂ from antarctic krill seemed to be a new type of anionic chymotrypsin.