Technical Tips for in vitro ALS Assay with The Herbicide Pyribenzoxim

The herbicide pyribenzoxim (Benzophenone O-[2,6-bis[(4,6-dimethoxy-2-pyrimidiyl) oxy]benzoyl]oxim) is a new pyrimidinyloxy benzoate herbicide that inhibits acetolactate synthase (ALS：EC 4.1.3.18). The compound is highly insoluble in water and this physicochemical property often complicates experiments in aqueous solutions such as in vitro enzyme assay. This short communication describes an optimal experimental condition for in vitro ALS assay of pyribenzoxim, and corrects editorial and experimental errors in the previous publications (Bae et al. 1997. Korean J. Weed Sci. 17：66, Roh et al. 2002, Korean J. Weed Sci. 21：349)