1. 1. The digestion proteases in five marine species (Atlantic halibut, Hippoglossus hippoglossus (L); Dover sole, Solea solea (L); turbot, Scophthalmus maximus, (L); European lobster, Hommarus gammaarus (L); and the giant prawn, Penaeus monodon) have been compared by biochemical methods. 2. 2. The pH profiles for the hydrolysis of casein by extracts from the digestive systems of each species showed different characteristics; extracts from adult halibut, turbot and sole exhibited strong pepsin-like activity; whereas this enzyme was absent in P. monodon and in sole larvae. 3. 3. Although lobster extracts, from either the hepatopancreas or the stomach, showed peaks at pH values of 5.8 and 2.5, this latter activity did not hydrolyse a specific substrate for pepsin. 4. 4. Halibut and turbot digestive extracts contained an activity optimal at pH values in the region of 5.0 resembling a cathepsin-like enzyme; an activity which was not evident in the other species under similar experimental conditions. 5. 5. Although all species possessed trypsin-like activity, the pH profiles of activity in the neutral to alkaline region were unique to each species. 6. 6. The significance of these results is considered with respect to the anatomical differences in the alimentary systems of these species. © 1989.
|Number of pages||5|
|Journal||Comparative Biochemistry and Physiology Part B: Comparative Biochemistry|
|Publication status||Published - 1989|