筋肉アルカリ性プロテアーゼ ＩＶ シログチおよびアカカマスとコイの筋肉内アルカリ性プロテアーゼの諸性質の比較

Abstract

The properties of purified alkaline proteases from white muscle of white croaker, Argyrosomus argentatus and barracuda, Sphyraena schlegeli, were studied and compared with those from carp muscle. The sedimentation constant (S020, w) and molecular weight were determined to be 19.6 S and 9.2×105 in the case of white croaker enzyme and 19.4S and 7.8×105 in the case of barracuda enzyme, respectively. These values were almost similar to the respective values for carp enzyme, i.e. 19.3S and 7.8×105. When the effects of temperature for 40min incubation were compared, the enzymes isolated from white croaker and barracuda reacted maximally at 61-63°C which is slightly lower than the optimal reaction temperature of the carp enzyme. The optimal pH of the marine fish enzymes ranged between 7.8 and 8.2, similar to that of the carp enzyme for caseinolysis. In contrast with carp enzyme which retained approximately 100% of the activity after heating at 60°C for 10 min, white croaker enzyme was completely inactivated and barracuda enzyme, by approximately 60%. The activities of the marine fish enzymes were stable in the pH range from 5.5 to 10.0 at 3°C for 20 hr. This range was slightly narrower than that of carp enzyme which is stable in the pH range of 4.5 to 10.0. No conspicuous differences were found between the properties of the marine fish enzymes and the carp enzyme.