魚筋肉のプロテアーゼ関する研究-III

酸性域で作用するプロテイナーゼの精製とその性質

抄録

A muscle proteinase acting at acid pH has been purified about 200 fold from carp ordinary muscle by the following procedure: (1) acid heat treatment of 0.5% KCl extract, (2) (NH₄)₂SO₄ fractionation, (3) acetone fractionation, and (4) Sephadex G-200 chromatography. The proteinase has a pH optimum at 2.8-3.0 and a temperature optimum for 1 hour reaction at near 50°C. It was stable at 37°C but lost its activity at 55°C rapidly. The proteinase was active on acid denatured hemoglobin, casein and myosin fraction protein. The enzyme did not hydrolyze synthetic substrate, CBZ-L-glu-L-tyr., BZ-L-arg-NH₂ and gly-L-tyr-NH₂ Na⁺, K⁺, Zn⁺⁺, Co⁺⁺, EDTA, KCN, cysteine and p-CMB did not affect the activity. Ni⁺⁺, glutathione and 2-mercaptoethanol activated the enzyme.