DETERMINATION OF 2-KETO ACIDS AND AMINO-ACIDS IN PLANT-EXTRACTS

2-keto acids and amino acids were extracted using liquid nitrogen and 0.25 N HCl. The keto acids and amino acids were seperated by cation exchange chromatography on AG50W-X8 resin. The cation exchange chromatography is vital for the determination of keto acids. The keto acids were derivatized with 1,2-diamino-4,5-methylenedioxybenzene (DMB), a specific derivatizing agent for 2-keto acids. The derivatized keto acids were quantified by reversed phase high performance liquid chromatography (HPLC). This assay is highly sensitive and can measure as low as 10 fmole of the keto acids per 10 mu l injection. The amino acids were analyzed by an automatic amino acid analyzer. These methods were used to show that 2-ketobutyrate (2-KB) and 2-aminobutyrate (2-AB) accumulate in plants treated with an acetohydroxyacid synthase inhibiting herbicide.