Lipid oxidation-induced oxidation in emu and ostrich myoglobins.
Emu and ostrich are ratites gaining increasing popularity as sources of low-fat meats. Secondary products of lipid oxidation, such as 4-hydroxy-2-nonenal (HNE), compromise myoglobin redox stability in a species-specific manner. However, the molecular basis of lipid oxidation-induced oxidation in ratite myoglobins has not been investigated. Therefore, our objective was to characterize lipid oxidation-induced oxidation in ratite myoglobins, in comparison with beef myoglobin. At physiological condition (pH7.4, 37 °C) HNE accelerated (P<0.05) oxidation of emu, ostrich, and beef oxymyoglobins. Autoxidation and HNE-induced oxidation were greater (P<0.05) in ostrich oxymyoglobin than in emu and beef oxymyoglobins. Mass spectrometric analyses revealed that HNE formed mono-adduct with both emu and ostrich myoglobins after 6h of incubation. Tandem mass spectrometry demonstrated that HNE adducted histidine 36 in ostrich myoglobin, whereas histidines 34 and 36 were adducted in emu myoglobin. The results indicate that primary structure of ratite myoglobins influences their redox stability in the presence of prooxidants.
Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40546, USA.
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Nair
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Suman
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Joseph
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Beach
D000447:Aldehydes / Q000032:analysis; D000818:Animals; D002417:Cattle; D020312:Dromaiidae; D006863:Hydrogen-Ion Concentration; D050356:Lipid Metabolism; D008460:Meat / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry*; D010084:Oxidation-Reduction; D020310:Struthioniformes; D053719:Tandem Mass Spectrometry
D000447:Aldehydes; D009211:Myoglobin; C017595:oxymyoglobin; C027576:4-hydroxy-2-nonenal
Lipid oxidation; Mass spectrometry; Myoglobin; Ratite; Redox stability