Effect Of Weak Magnetic Field On Hydrolysis Activity And Conformation Of Antioxidant Peptide Proteinase

Collichthys niveatus is a common low-value fish in China.It is an important marine resource in China because of its huge catch and wide distribution of its origin.However,due to its smaller body and more fish bones,its meat is mostly used for processing low-value products such as surimi.In recent years,the ocean has been praised as a treasure house for searching and exploring many bioactive substances,including antioxidant peptides.Many kinds of bioactive polypeptides can be prepared by enzymatic hydrolysis of aquatic products and their by-products.However,the activity of antioxidant peptides still needs to be improved.In this experiment,the activity of antioxidant peptides of active polypeptides was investigated by trypsinase hydrolysis of fish treated with weak magnetic field.The properties and structure of trypsinase before and after treatment with weak magnetic field were analyzed,and the mechanism of the effect of weak magnetic field on the activity of trypsinase was explored.The main conclusions are as follows:1.Trypsin was treated with weak magnetic field of different intensity and time,and enzymatic hydrolysis of fish was carried out to detect the change of antioxidant activity of enzymatic hydrolysate.Compared with untreated polypeptide,the scavenging rate of hydroxyl radicals,superoxide anion and DPPH radicals increased by 16.41%,17.71% and 10.59%,respectively.2.By analyzing the properties of trypsin before and after treatment with weak magnetic field,it is concluded that the activity of trypsinase after treatment with weak magnetic field is 52.5 TAME units higher than that before treatment(the value of enzyme activity is expressed in units);the trypsinase after treatment with weak magnetic field has no significant change in the optimum pH;the optimum temperature of trypsinase before and after treatment with weak magnetic field changes from 37 to 45 before and after treatment with magnetic field.The kinetic parameters of post-trypsinase were studied.The Km value of trypsinase before treatment was 0.02310,Vmax value was 1.3650,the Km value of trypsinase after treatment was 0.01651,and Vmax value was 1.3702.The results showed that the affinity of trypsinase with substrate was enhanced and the reaction speed was accelerated after treatment with weak magnetic field.3.By studying the conformation of trypsin before and after treatment with weak magnetic field,it was found that the relative molecular weight of trypsin was about 24 kDa after treatment with weak magnetic field.The content of amino acid decreased and the proportion of essential amino acid increased.DSC results showed that the enthalpy of trypsin changed;infrared spectrum showed that its maximum absorption peak shifted to the right;ultraviolet spectrum showed that its absorption intensity decreased;Alpha-helix,beta-fold,beta-turn and irregular curl have changed in varying degrees.