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. This enzyme was inhibited by DFP, PMSF, soybean trypsin inhibitor, but not TLCK, leupeptin, or antipain. Proteinase A2 could hydrolyze benzoyl–tyrosine–ethylester and was inhibited by chymostatin.These results suggest that proteinase A2 from antarctic krill seemed to be a new type of anionic chymotrypsin.