Related Experiment Video
Updated: Aug 16, 2026

Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
Published on: November 1, 2012
μ-Calpain oxidation and proteolytic changes on myofibrillar proteins from Coregonus Peled in vitro
Pingping Liu1, Zhiwei Zhang1, Xin Guo1
1School of Food Science and Technology, Shihezi University, Shihezi 832003, Xinjiang, China.
Abstract:
The purpose of this study was to investigate the structural properties of μ-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 μ-calpain changed significantly after oxidation. The content of α-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 µ-calpain molecules. Changes in µ-calpain structure could improve the activity of µ-calpain, reaching the highest value at 0.5 mM H2O2. The highest µ-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, µ-calpain, and MP degradation.
Related Concept Videos
Proteins: From Genes to Degradation
Transcription is the synthesis of RNA molecules by RNA...
Translocation of Proteins into the Mitochondria
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Caspases
Proteins: From Genes to Degradation
Transcription is the synthesis of RNA molecules by RNA...
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Smooth Muscle Contraction
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...

