Endogenous Proteases in the Head of Litopenaeus vannamei

With the increase of resource requirements and environmental concerns, the efficient utilization of shrimp head waste is in urgent demand by using the method of endogenous protease autolysis. However, there is little information on the types, amounts and properties of endogenous proteases in shrimp heads. The aim of this paper is to propose a method for isolating and analysing the endogenous proteases in the head of Litopenaeus vannamei . After sampling from L. vannamei , the protease activity of the crude enzyme extract was measured, followed by determination of inhibition ratios using protease inhibitors PMSF, SBTI, and EDTA. Ammonium sulphate precipitation and gel chromatography were employed to purify the proteases. Finally, gelatin protein electrophoresis was performed. Determination of the protease activity of the crude enzyme extract from the head, meat and shell reveals that the endogenous proteases are mainly distributed in the shrimp head. The crude enzyme extract of shrimp head contains trypsin and pepsin. Adopting a synthetic method, we have successfully realized to isolate, purify and identify 14 types of endogenous proteases from the head of L. vannamei for the first time, and accordingly to investigate the enzymatic activities, hydrolysis properties and gelatin zymogram of the isolated proteases. An effective method for isolating and analysing the endogenous proteases in the head of L. vannamei has been developed on the basis of ammonium sulphate precipitation, gel chromatography and gelatin protein electrophoresis. The establishment of this synthetic method may make a significant contribution to the utilization of shrimp head waste.