Title

Effects of lipid oxidation products on oxymyoglobin oxidation and structure

Date of Completion

January 2002

Keywords

Agriculture, Food Science and Technology

Degree

Ph.D.

Abstract

The redox stability of the heme protein myoglobin (Mb) is impacted by many factors, including lipid oxidation and its products. α,β-unsaturated aldehydes are secondary products derived from the oxidation of ω-6 polyunsaturated fatty acids. 4-hydroxy-2-nonenal (HNE) is a particularly reactive and cytotoxic α,β-unsaturated aldehyde known to chemically modify proteins and accelerate equine cardiac OxyMb oxidation. This research was conducted to determine the influence of HNE on bovine skeletal OxyMb redox stability in-vitro, to identify HNE adduction sites on Mb and to characterize physico-chemical changes as a result of HNE adduction. Using LC-MS, LC-MS/MS, Western blotting, circular dichroism, and differential scanning calorimetry it was shown that HNE forms adducts at several histidine (HIS) residues of Mb and accelerates heme iron oxidation in the protein. Perturbations in Mb structure as a result of HNE adduction appeared to be minor, but significantly altered redox stability of the protein thereby offering a partial explanation of the interaction of Mb and lipid oxidation. ^