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

Theobjective of the current study was to evaluate the effectsof lipid peroxidation products, malondialdehyde (MDA), hexenal, and4-hydroxynonenal (HNE), on calpain-1 function, and liquid chromatographyand tandem mass spectrometry (LC-MS/MS) identification of adductson calpain-1. Calpain-1 activity slightly increased after incubationwith 100 mu M MDA but not with 500 and 1000 mu M MDA. However,calpain-1 activity was lowered by hexenal and HNE at 100, 500, and1000 mu M. No difference in calpain-1 autolysis was observed betweenthe control and 1000 mu M MDA. However, 1000 mu M hexenaland HNE treatments slowed the calpain-1 autolysis. Adducts of MDAwere detected on glutamine, arginine, lysine, histidine, and asparagineresidues via Schiff base formation, while HNE adducts were detectedon histidine, lysine, glutamine, and asparagine residues via Michaeladdition. These results are the first to demonstrate that lipid peroxidationproducts can impact calpain-1 activity in a concentration-dependentmanner and may impact the development of meat tenderness postmortem.