Effects of hydroxyl radical oxidation on myofibrillar protein and its susceptibility to μ-calpain proteolysis. (February 2021)

• Record Type: Journal Article
• Authors: Zhang, Zhiwei; Liu, Pingping; Deng, Xiaorong; Guo, Xin; Mao, Xiaoying; Guo, Xiaobing; Zhang, Jian
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 137(2021)
• Publication Date: 2021-02
• Subjects: Myofibrillar protein -- Hydroxyl radical -- Protein oxidation -- μ-Calpain -- Protein degradation; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2020.110453
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: In the present study, the modification of myofibrillar protein (MP) by hydroxyl radicals (·OH) and the effects of oxidative modification on the proteolysis of MP by μ-calpain were investigated. Isolated MP was exposed to different oxidation conditions and then incubated with μ-calpain. With increasing H2 O2 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 α-helix content decreasing from 19.19% to 17.32% whereas the β-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 ·OH can change the structure of MP and its susceptibility to proteolysis by μ-calpain, providing mechanistic information that links protein oxidation with proteolysis. Graphical abstract: Image 1 Highlights: C. peled myofibrillar protein (MP) is particularly vulnerable to oxidation. Oxidative stress has a detrimental effect on protein structure. The oxidative modification of MP alters its susceptibility to μ-calpain proteolysis. Protein oxidation may be an important factor affecting the fish texture tenderness postmortem.