Chromatography of Indole Derivatives on Sephadex G-15

Sa？etak The chromatographic · properties of indole derivatives, mainly biogenetically related to the plant growth hormone, indole-3-acetic acid, were studied on Sephadex G-15. The eluents used were 70°/o and 30°/o aqueous methanol, volatile ethylenediamine-acetate buffers of pH 4.2 and 7.4, and distilleo water adjusted to pH 7.4. The adsorption of indole derivatives to Sephadex could be preferentially ascribed to the heterocyclic nucleus which is bound by rt complex formation, as well as by hydrogen and hydrophobic bonding. The presence of a side chain, if subject to the same type of binding forces, results not only in stronger sorption but also in some exclusion in accordance with molecular weight. Furthermore, because of the carboxyl groups contained in Sephadex gels, positively charged compounds are bound by ion exchange, whereas negatively charged ones are acted upon by Donnan ion exclusion forces