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 ex change chromatography on AG50W-X8 resin. The cation exchange chromatog raphy is vital for the determination of keto acids. The keto acids wer e derivatized with 1,2-diamino-4,5-methylenedioxybenzene (DMB), a spec ific derivatizing agent for 2-keto acids. The derivatized keto acids w ere quantified by reversed phase high performance liquid chromatograph y (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 an alyzed 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 herbic ide.