抄録
We show the distribution, characterization, and application of chitinolytic enzymes in squid, especially chitinase. Measurement of chitinase and β-N-acetylhexosaminidase activities was investigated in the various organs of four species of squid. Both enzyme activities were detected in the digestive organs and liver of all species examined. Chitinases were purified from the liver of Japanese common squid and arrow squid by ammonium sulfate fractionation and column chromatography. The purified enzymes were basic chitinases with molecular masses of 38-42 kDa. The chitinases hydrolyzed glycol chitin and colloidal chitin, but not pNp-GlcNAc and Micrococcus lysodeikticus. Squid liver chitinases hydrolyzed GlcNAc4 to two molecules of GlcNAc2, GlcNAc5 to GlcNAc2 plus GlcNAc3, and GlcNAc6 to two molecules of GlcNAc3, and GlcNAc2 plus GlcNAc4. Preparation of GlcNAc, which is used in food industry, was investigated using crude enzyme solution prepared from the liver of Japanese common squid. The enzyme decomposed insoluble chitin and produced reducing sugar. GlcNAc was detected in the enzymatically hydrolyzed colloidal chitin solution.
