μ-Calpain oxidation and proteolytic changes on myofibrillar proteins from Coregonus Peled in vitro

The purpose of this study was to investigate the structural properties of mu-calpain induced by hydroxyl radical oxidation and its effect on the degradation of myofibrillar protein (MP) from the dorsal muscles of Coregonus peled. The carbonyl and sulfhydryl content of mu-calpain changed significantly after oxidation. The content of alpha-helix in the secondary structure decreased from 0.825 to 0.232 and the changes in intrinsic fluorescence and ultraviolet (UV) absorption spectra indicated that oxidation could cause the expansion and aggregation of mu-calpain molecules. Changes in mu-calpain structure could improve the activity of mu-calpain, reaching the highest value at 0.5 mM H2O2. The highest mu-calpain activity facilitate the degradation of unoxidized MP, while the degradation of oxidized MP was facilitated at the 1 mM H2O2. Thus, our results provide a scientific basis for the interaction mechanism among hydroxyl radical oxidation, mu-calpain, and MP degradation.

Automated summary

The study revealed that hydroxyl radical oxidation significantly altered the structural properties of mu-calpain, affecting its activity and degradation of myofibrillar protein. The highest mu-calpain activity facilitated the degradation of unoxidized myofibrillar protein, while the degradation of oxidized myofibrillar protein was influenced by the concentration of oxidant.