Characterization of amylase and protease activities in the digestive system of Concholepas concholepas (Gastropoda, muricidae)

Abstract

ABSTRACTConcholepas concholepas (loco) is a carnivorous gastropod that inhabits the coast of Chile and Peru. Its fisheries showed a great importance in the past decades, however, now mainly relies on artisanal management of wild stocks. Feeding is one of the important factors that have restrained the establishment of large scale field rearing of loco. C. concholepas food preferences consist of mytilids and cirripeds, however its digestive physiology has not been studied and its digestive enzymes have not been yet characterized. The purification of amylase and protease from the digestive gland and the gland of Leiblein of C. concholepas were performed by ionic exchange chromatography (DEAE-cellulose), and substrate-PAGE indicated the presence of the amylase and protease in the fractions collected from the column. Amylase enzymatic assays showed its maximum activity at pH 7.0 and 50°C in the digestive gland. Protease on the other hand showed a great acidic activity, specifically at pH 3.0 in both organs, also at 50°C. Inhibition of the amylolytic activity was observed in the presence of EDTA, and metal ions like MnCl2, MgCl2, ZnSO4, while it was enhanced in the presence of CaCl2, NaCl, KCl. Protease inhibition assays were also performed evidencing mainly the presence of aspartic proteases and a low but not inexistent presence of serine proteases. Our results provide evidence of important proteolytic but also amylolytic activities present in the digestive system of loco, providing evidence that this mollusc has wider digestive capabilities than initially though, which could potentially lead to the development of alternative food diets.