Further studies on the roles of proteases in the activation of phenolase from Norway lobster (Nephrops norvegicus)

Phenolase activation in Norway lobster (Nephrops norvegicus) was found to be a result of proteolysis. Endogenous protease activity is shown to activate the phenolase activity directly. The three protease activities identified in Norway lobster all affected the phenolase-activation process. Protease III, a metal-dependent serine protease, was involved in the activation process, but proteases I and II, two thiol proteases, also affected the activation process by apparently degrading the phenolase present. The phenolase activation in Norway lobster appears to be a result of the balance of the specific proteolytic action of protease III and the presumably less discriminative degradation of protease I and II.