Abstract
In plants, a large part of fatty acids in membrane is comprised from polyunsaturated fatty acids. In this study, protein modification caused by polyunsaturated fatty acid peroxidation products was examined by immunochemical analysis. Results obtained by a model experiment using reaction mixture contained model protein (BSA or Rubisco) and C18 unsaturated fatty acid methyl ester showed that protein modification was most effectively caused by peroxidation of linolenic acid (18:3) and were extremely promoted over 33°C in the presence of a metal-catalyzed oxidation system (Fe3+/ascorbate/O2). Detectable protein adducts were derived from reactive aldehydes such as malondialdehyde, acrolein and crotonaldehyde. When isolated thylakoid membrane was peroxidized at 37°C in the presence of a metal-catalyzed oxidation system, protein modification by malondialdehyde was also detected in intact plants stressed at 40°C under illumination. Thus, protein modification might account for a part of damage of heat stressed plants.
