Latent egg capsule catechol oxidase in the little skate (Raja erinacea)

Abstract

Abstract 1. 1. Treatment of crude catechol oxidase from Raja erinacea nidamental gland with α-chymotrypsin reduced the latency period following o- diphenol addition and increased initial rates of substrate oxidation [Koob and Cox (1985) Bull. Mt Desert Is. Biol. Lab.25, 132–134; Koob and Cox (1988) Biol. Bull.175, 202–211]. 2. 2. Nidamental gland extracts prepared wth proteinase inhibitor cocktail or with phenylmethylsulfonyl fluoride alone displayed rates of 4-methylcatechol oxidation 17 and 13% those of control values, respectively. 3. 3. Initial lag period duration was increased more than 10-fold in these extracts. 4. 4. α-Chymotrypsin had little effect on lag period or oxidation rates of extracts containing proteinase inhibitors. 5. 5. Likewise, α-chymotrypsin did not induce catechol oxidase activity in dialyzed inhibitor extracts. 6. 6. These results indicate that a serine enzyme is required for catechol oxidase activation and that α-chymotrypsin does not act directly on the latent oxidase, but rather upon another factor(s) involved in activation. 7. 7. Activation of this latent catechol oxidase therefore appears to involve a multi-step cascade which could serve to regulate catechol oxidase activity precisely during skate egg capsule formation.