Effects Of Recombinant UK114 Protein On Calpain And Calpastatin-mediated Water Migration In Post-mortem Beef

In this paper,we investigated the effects of calpain-activated protein UK114 on calpain and calpastatinmediated water migration after beef slaughter,to provide a new idea for studying the change of water retention in post-mortem muscles,so as to provide a basis for the control of cold meat juice loss.In this experiment,the longest muscle of the beef cattle back was used as experimental material.Calpain-1,calpastatin and recombinant UK114 protein were added in the body.After slaughter,the cells were incubated for different time to determine the shear force,fragmentation index(MFI)and apparent water holding capacity of the muscle.Changes in water composition and distribution;extraction of myofibrillar proteins,SDS-PAGE gel electrophoresis,determination of surface hydrophobicity,solubility,protein secondary structure,etc.of myofibrillar proteins,respectively,to explore recombinant UK114 protein Effects of calpain and calpastatin on water migration in post-mortem beef.The results showed that with the prolongation of incubation time,the hydrophobicity of the protein surface first increased and then decreased,and the solubility decreased first and then increased.The extreme points of hydrophobicity and solubility after adding calpain are advanced from 72 h to 48 h;when UK114 and calpain were added simultaneously,the extreme point was advanced to 24 h;after adding calpastatin,the hydrophobicity began to decrease at 120 h,and the extreme point of solubility was postponed from 72 h to 120 h;but when both UK114 and calpastatin were added After that,the extreme point was advanced to 48 h,the solubility increased,and the WHC increased.The content of bound water in muscle was lower,and the change was smaller.Adding UK114 and calpain is more expensive than adding calpain to non-flowable water,and the P22 content of free water P23 was significantly negatively correlated.The change of muscle pressure loss rate after slaughter is first rise and then fall.After adding UK114 and calpain or UK114 and calpastatin,the pressure loss rate was significantly correlated with hydrophobicity,solubility and P22 and P23.After adding calpain,the content of ?-helix in myofibrillar protein began to increase at 48 h.,and the ?-helix content began to increase after 24 hours of incubation with the UK114 and calpain.The ?-sheet content decreased,the protein secondary structure stability increased,and the water holding capacity increased.After adding calpastatin The content of ?-helix in myofibrillar protein began to increase at 120 h,and the ?-helix content in the test group supplemented with UK114 and calpastatin began to increase at 48 h.The above studies showed that the addition of calpain would promote the migration of water in muscles.The addition of UK114 protein enhanced the promotion of calpain-mediated water migration.The addition of calpastatin inhibited the water migration in muscles.Inhibition of calpastatin-mediated water migration was inhibited by the addition of UK114 protein.