首页|Effects of hydroxyl radical oxidation on myofibrillar protein and its susceptibility to mu-calpain proteolysis
Effects of hydroxyl radical oxidation on myofibrillar protein and its susceptibility to mu-calpain proteolysis
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NSTL
Elsevier
In the present study, the modification of myofibrillar protein (MP) by hydroxyl radicals (center dot OH) and the effects of oxidative modification on the proteolysis of MP by mu-calpain were investigated. Isolated MP was exposed to different oxidation conditions and then incubated with mu-calpain. With increasing H2O2 concentration, the carbonyl and dityrosine contents as well as the surface hydrophobicity of the MP increased, while the total sulfhydryl groups and tryptophan fluorescence intensity gradually decreased. Disulfide bonds and other covalent bonds resulted in the cross-linking and aggregation of proteins. Increasing oxidant concentration resulted in the alpha-helix content decreasing from 19.19% to 17.32% whereas the beta-sheet content increased from 21.59% to 26.47%. Protein oxidation increased the proteolytic susceptibility of actin, but inhibited the proteolysis of myosin heavy chain, troponin T, and desmin. Overall, our data demonstrate that center dot OH can change the structure of MP and its susceptibility to proteolysis by u-calpain, providing mechanistic information that links protein oxidation with proteolysis.
NSTL
Elsevier
