著者
関 伸夫 酒谷 博史 小野沢 鉄彦
出版者
公益社団法人 日本水産学会
雑誌
日本水産学会誌 (ISSN:00215392)
巻号頁・発行日
vol.43, no.8, pp.955-962, 1977-08-25 (Released:2008-02-29)
参考文献数
12
被引用文献数
18 18

Proteases were extracted from antarctic krill, Euphausia superba, with borate buffer at pH 8.0 They were partially purified by ammonium sulfate fractionation and gel filtration through Sephadex G-100. Further. purification performed with chromatohraphy on DEAE-Sephadex A-50 separated them into two trypsin-like proteases and a protease of unknown specificity. The trypsin-like proteases were characterized by their hydrolysis of TAME as well as the inhibition of the activity in the presence of soy-bean trypsin inhibitor. However, the inhibition of the two tryptic activities by PMSF was less than that in the case of bovine trypsin. All three proteases showed optimal activity at the physiological pH (around 8.0) of krill body fluids. They were stable only in an alkaline medium and digested carp actomyosin. These results suggest that they are responsible for the rapid autolysis of krill body protein which occurs after catching.
著者
関 伸夫 宇野 秀樹 李 南赫 木村 郁夫 豊田 恭平 藤田 孝夫 新井 健一
出版者
日本水産學會
雑誌
日本水産学会誌 (ISSN:00215392)
巻号頁・発行日
vol.56, no.1, pp.125-132, 1990
被引用文献数
39 152

When carp myosin B was incubated at 25°C, SDS-PAGE showed that an addition of a soluble extract from Alaska pollack muscle and surimi greatly stimulated the cross-linking reac-tion of myosin heavy chains. This effect was completely lost on boiling but not with dialysis, suggesting the presence of an active enzyme, transglutaminase, in the extract. It was, therefore, purified from Alaska pollack muscle by DEAE-cellulose chromatography and Sephadex G-200 gel filtration.<br> The partially purified enzyme catalyzed the cross-linking reaction of myosin heavy chain and also showed an activity to incorporate a fluorescent amine, monodansylcadaverine, into acety-lated casein. SDS-PAGE analysis of carp myosin B incubated with the enzyme in the presence of monodansylcadaverine showed several fluorescent bands, including myosin heavy chain and its polymers, with a depletion of fluorescence on actin, tropomyosin and connectin bands. The transglutaminase activity was found at a molecular weight of about 85, 000 by the gel filtration and required Ca<sup>2+</sup>.<br> From these results, the presence of transglutaminase was ascertained in Alaska pollack muscle and surimi. The setting of the salted paste of muscle or surimi may thus involve at least the enzymatic process in gel network formation.