Obtainment and characterization of digestive aspartic proteases from the fish Caranx hippos (Linnaeus, 1766).

J A F Silva,M L E Leal,T A Silva,L D A Costa,R S Bezerra,A C V Freitas-Júnior,H M S Costa,M K S Silva

doi:10.1590/1519-6984.234500

Abstract

This work aimed to obtain aspartic proteases of industrial and biotechnological interest from the stomach of the crevalle jack fish (Caranx hippos). In order to do so, a crude extract (CE) of the stomach was obtained and subjected to a partial purification by salting-out, which resulted in the enzyme extract (EE) obtainment. EE proteases were characterized physicochemically and by means of zymogram. In addition, the effect of chemical agents on their activity was also assessed. By means of salting-out it was possible to obtain a purification of 1.6 times with a yield of 49.4%. Two acid proteases present in the EE were observed in zymogram. The optimum temperature and thermal stability for EE acidic proteases were 55 ºC and 45 °C, respectively. The optimum pH and pH stability found for these enzymes were pH 1.5 and 7.0, respectively. Total inhibition of EE acid proteolytic activity was observed in the presence of pepstatin A. dithiothreitol (DTT) and Ca2+ did not promote a significant effect on enzyme activity. In the presence of heavy metals, such as Al3+, Cd2+ and Hg2+, EE acidic proteases showed more than 70% of their enzymatic activity. The results show that it is possible to obtain, from the stomach of C. hippos, aspartic proteases with high proteolytic activity and characteristics that demonstrate potential for industrial and biotechnological applications.

Highlights

The crevalle jack fish, Caranx hippos (Linnaeus, 1766), is a migratory species that belongs to the family Carangidae
Partial purification of the Crude Extract The crude extract (CE) obtained from the stomach of C. hippos showed a total specific activity of 439 mU.mg-1
The use of a simple step for partial purification of the crude extract and concentration of enzymes is an economic advantage for the commercial use of this material in industrial processes that do not demand a high degree of purity of the enzymes, such as in the extraction of collagen and production of fermented fish

Summary

Introduction

The crevalle jack fish, Caranx hippos (Linnaeus, 1766), is a migratory species that belongs to the family Carangidae They are predatory animals, feeding on smaller fish and some invertebrates, and when young they prefer zooplankton and crustaceans (Luque and Alves, 2001). This species has a worldwide distribution and can be found in the American continent from the Caribbean to the coast of Uruguay.

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