Identification and Quantitative Analysis of Indole-3-Acetyl-l-Aspartate from Seeds of Glycine max L.

Indole-3-acetyl-l-aspartate (IAAsp) was isolated from seeds of Glycine max L. cv. Hark and its identity established by its chromatographic performance and its mass spectral fragmentation. Following acid hydrolysis, the aspartate moiety was shown to be the l-enantiomer by reverse phase high performance liquid chromatographic retention time of the bisethyl ester derivatized with 2,3,4,6-tetra-O-acetyl-beta-d-glycopyranosyl isothiocyanate. Isotope dilution analysis using [(14)C]IAAsp as internal standard showed that soybean seed contained 10 mumol/kg IAAsp and this accounted for one-half of the total indoleacetic acid of the seed.