Identification of N alpha-acetyl-epsilon-(2-propenal)lysine as a urinary metabolite of malondialdehyde.
Although orally administered malondialdehyde (MDA), a reactive hepatotoxic and mutagenic product of lipid peroxidation, is extensively metabolized to CO2, a portion is excreted in the urine in acid labile “bound” forms. Since much of the MDA in the diet is apparently bound to protein, the metabolism of protein-bound MDA was investigated. MDA was reacted with serum albumin and fed to rats. A urinary metabolite was detected which was shown to be identical to a metabolite of the lysine-MDA enaminal N epsilon-(2-propenal)lysine. After isolation by ion exchange and high performance liquid chromatography the metabolite was identified using high field nuclear magnetic resonance spectroscopy and fast atom bombardment-mass spectroscopy as N alpha-acetyl-epsilon-(2-propenal)lysine. This compound also was a major urinary metabolite of the Na enol salt of MDA administered by stomach intubation, and was excreted in increased amounts by rats fed a diet containing a highly peroxidizable oil (cod liver oil). It was also detected in the urine of fasted animals after injection with NaMDA, indicating that it is formed as a product of lipid peroxidation in vivo as well as of peroxidation of dietary lipids.
Chemistry and Geology
Journal of Biological Chemistry
McGirr, L. G., Hadley, M., & Draper, H. H. (1985). Identification of N alpha-acetyl-epsilon-(2-propenal)lysine as a urinary metabolite of malondialdehyde. The Journal of Biological Chemistry, 260(29), 15427–15431. https://doi.org/10.1016/S0021-9258(17)36271-3
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Copyright © 1985 American Society for Biochemistry and Molecular Biology.