Submitted to: Western Society of Weed Science Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/8/1999
Publication Date: N/A
Technical Abstract: Pyrithiobac inhibition of crude extracts of ALS from Palmer amaranth exhibit a thermal dependence. Relative inhibitor potency (I_50) values ranged from 6.4 nM at 30 degrees C to 22.5 nM at 50 degrees C, more than a three-fold difference. Additionally, ALS isozymes from Palmer amaranth have been identified and isolated. This research sought to characterize the thermal dependence of pyrithiobac inhibition of the ALS species isolated from Palmer amaranth. ALS from Palmer amaranth was extracted from plants 5- 10 cm in height. The extract was desalted and then purified through a series of steps utilizing ion exchange column and gel filtration chromatography to separate species by molecular weight. Molecular weights were determined by applying standards to the gel filtration column. Assays of pyrithiobac inhibition of the molecular species were performed under saturating substrate conditions at various temperatures to determine the thermal dependence of the inhibition of the species.