Comparison of digestive proteinases in three penaeids

a r t i c l e i n f o Recently, several groups of researchers reported that besides serine proteinases, other classes of proteinases may be involved in crustacean's food protein digestion, including cysteine and aspartic proteinases. In this paper, a comparative study of the class and type of digestive proteinases of whiteleg shrimp Penaeus vannamei, blue shrimp Penaeus stylirostris, and yellowleg shrimp Penaeus californiensis is addressed, along with some operational characteristics. The substrate-SDS-PAGE zymogram of the three species showed varieties of different proteinases that were species-specific and proteinase composition that may be used for species identification or population studies. In the three species, trypsin and chymotrypsin were present as isoenzymes. Some active bands were active at acid pH and were partially inhibited by pepstatin A and based on bibliography information they are digestive enzymes. The involvement of these enzymes in food protein digestion is discussed and compared with digestive enzymes present in other decapod species. This and additional information expand the knowledge about enzyme food protein digestion in crustaceans, making clear that digestion process is more complex than previously alleged and if common patrons exist, there are some individualities. This information opens a line of research trying to fully understand the mechanism of protein digestion. With the advent of genomic era, nutrition and food sciences are moving to individualize or personalize food and nutrition, and ultimately health by tailoring the food to the individual or population genotype, this merged science is called Nutrigenomics. Into doing so, it is necessary to identify what genome derived molecules are involved in processing food. In this study we describe proteinases of digestive system of three commercial shrimp species, including operational parameters. This information, with others to come, will help to understand if proteinases, as it happens for Penaeus vannamei, are present as isoenzymes, enzymes with same specificity for the substrate and reaction but coming from different genes, and can be used as population markers for feeding trials while aquafarming. The research is supported by the knowledge that shrimp nutritional, functional and organoleptic properties are influenced by what is fed and how food or feed is processed by the digestive system. Other important potential contribution is that the precise knowledge of enzymes present in the digestive gland of penaeids may help to design strategies to extend the shelf life of the seafood product. Hydrolyzing of exogenous protein by the digestive system and endogenous …