The Detection of Isomers of 4–Hydroxyisoleucine by the Jeol Amino Acid Analyser and by TLC

Abstract

When a solution of (2S, 3R, 4R)–4–hydroxyisoleucine (the main free amino acid of fenugreek seed) in buffer at pH 2.2 was left to stand for 24 h and then run under the standard conditions of the Jeol Amino Acid Analyser, three peaks were obtained, whereas in deionised water at pH 5.5 only one peak was obtained at 92 min. When the (2R, 3R, 4R)–isomer was used under the same conditions a single peak was also obtained at 92 min. These peaks corresponded to the lactone forms of the isomers. This is discussed and the separation of the various isomers of 4–hydrqxyisoleucine and their lactones by TLC is described.

4–Hydroxyisoleucine - Fenugreek - Amino Acid