Lipid Peroxidation Products Influence Calpain-1 Functionality In Vitro by Covalent Binding

Area of Science:

• Biochemistry
• Food Science
• Proteolysis

Background:

• Calpain-1 is a key protease involved in postmortem meat tenderization.
• Lipid peroxidation products are reactive aldehydes formed during fat oxidation.
• The interaction between lipid peroxidation products and calpain-1 is not well understood.

Purpose of the Study:

• To investigate the impact of malondialdehyde (MDA), hexenal, and 4-hydroxynonenal (HNE) on calpain-1 activity and autolysis.
• To identify specific adducts formed on calpain-1 by these lipid peroxidation products.

Main Methods:

• Incubation of purified calpain-1 with varying concentrations of MDA, hexenal, and HNE.
• Assay of calpain-1 activity and autolysis rates.
• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for adduct identification.

Main Results:

• MDA showed a slight increase in calpain-1 activity at 100 μM, but inhibition at higher concentrations.
• Hexenal and HNE inhibited calpain-1 activity and slowed autolysis at all tested concentrations (100–1000 μM).
• MDA and HNE adducts were identified on specific amino acid residues (e.g., histidine, lysine) of calpain-1.

Conclusions:

• Lipid peroxidation products modulate calpain-1 activity and autolysis in a concentration-dependent manner.
• Adduct formation on calpain-1 by these aldehydes provides a mechanism for functional alteration.
• These findings suggest a role for lipid peroxidation in influencing meat tenderness postmortem through calpain-1 modification.