Figure 4.

Effect of AAPH treatment on the formation of dityrosine in different protein fractions. Proteins were treated with indicated concentrations of AAPH at 37°C for 5 hr. Dityrosine (nmol/mg protein) in three different fractions of AAPH-treated proteins were determined and quantitated as described. Total represents total protein fraction after AAPH treatment, sup represents supernatant fraction of AAPH-treated proteins after separation of precipitate, and ppt represents precipitate fraction of AAPH-treated proteins. Open bars represent the results of 2-month-old rat liver proteins, and solid bars represent those of 24-month-old rat liver proteins. Results are presented as the average of two independent experiments.