Myricetin inhibited O2− generation due to the reduced form of XOD. Myricetin reversibly inhibited the formation of uric acid in a mixed-type manner. Myricetin bound to the site around isoalloxazine ring in the FAD domain. Van der Waals forces and hydrogen bonds dominated the binding process. Binding of myricetin to XOD induced the conformational change of XOD.