Effects of oxidation on the physicochemical properties and degradation of mutton myofibrillar proteins

Tenderness affects mutton quality and price, and the degradation of myofibrillar protein (MP) is critical to improve tenderness. We investigated the oxidative modification of mutton MP by hydroxyl radicals (OH) and the effects of this modification on the proteolysis of MP by mu-calpain. As the H2O2 concentrations increased, the carbonyl and dityrosine contents and the surface hydrophobicity of MP all display an increasing trend, whereas the total sulfhydryl and intrinsic fluorescence intensity of MP declines significantly. SDS-PAGE electrophoresis indicates that disulfide bonds and other covalent bonds led to protein cross-linking and aggregation. After adding mu-calpain, with increasing oxidation, the degradation percentage of myosin heavy chain (MHC) increases considerably and actin degradation is promoted, while the proteolysis of troponin-T and desmin is inhibited. These data suggest that center dot OH can change MP physicochemical properties and its susceptibility to mu-calpain. Future investigations will focus on the effect of oxidation on the degradation of MP by other proteases, such as cathepsins and caspase and the effect of oxidation on these enzymes.

Automated summary

This study investigated the oxidative modification of mutton myofibrillar protein (MP) by hydroxyl radicals (OH) and its impact on the proteolysis of MP by mu-calpain. The results showed that OH can alter the physicochemical properties of MP and its susceptibility to mu-calpain.