Histone lysine benzoylation may occur by Gcn5-catalyzed and nonenzymatically ways in vivo. In this project, we identified several Kbz sites on Xenopus laevis octamer in the absence or presence Gcn5-Ada2 complex in vitro, respectively. The number 672 represents the data in the absence of Gcn5-Ada2, and the number 674 represents the data that in the presence of Gcn5-Ada2.