THE DIGESTIVE PROTEASES OF LANGOSTILLA (PLEURONCODES-PLANIPES, DECAPODA) - THEIR PARTIAL CHARACTERIZATION, AND THE EFFECT OF FEED ON THEIR COMPOSITION

1. Three methods of recuperating and preserving enzyme activity from freshly-caught langostilla were assessed. In the pressing and acetone extract methods, the recovered specific activity was similar. 2. Protease activity was higher between 6.5 and 8 pH, and was sensitive to high temperatures. 3. In PAGE and serine inhibition assays, one fraction resembled bovine trypsin. 4. The composition of proteins and molecules bearing protease activity from the hepatopancreas and stomach of both fed and starved animals was similar, indicating proteases are not induced but constitutive.