A Trypsin from Euphausia Pacifica (TEP B): Functional Groups and Effects of Metal Ions

Xiang, P.; Wu, Z.; Niu, W.; Ye, Y., and Lin, M., 2018. A trypsin from euphausia pacifica (TEP B): Functional groups and effects of metal ions. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 392–396. Coconut Creek (Florida), ISSN 0749-0208. Euphausia pacifica is a widely distributed euphausiid of Chinese coastal waters with a large biomass. It is a kind of seafood with high nutritive value, indicates to be a potential large massive protein resource. A 32.3 kDa trypsin (TEP B) with isoelectric point 4.3 and amidase activity was purified and identified from E. pacifica. The effects of metal ions and the modifications of chemicals on the functional groups of TEP B were performed. The activity of TEP B was activated by 0.3-0.5 mmol Ca2+ and Mg2+, and was inhibited by 0.1-0.5 mmol Zn2+, Cu2+, Pb2+ and Hg2+; the effect of TEP B was promoted with 0.2 mmol Mn2+, but inhibited with 0.5 mmol Mn2+. The cysteine, tryptophan, histidine and arginine residues of TEP B are essential to the activity, stability and flexibility; lysine, aspartic or glutamic residues of TEP B are not located in the activity site. The study provides supplement to digestive physiology of crustacean.