PURIFICATION, CHARACTERIZATION AND DEVELOPMENTAL EXPRESSION OF INDOLE-3-ETHANOL OXIDASE FROM SEEDS OF PHASEOLUS-VULGARIS

Purification of indole-3-ethanol (IEt) oxidase was carried out from ex tracts of the seeds of two bean cultivars. The IEt oxidase from the La brador cultivar was purified more than 1000-fold and had a molecular w eight of about 56 kD. The enzyme reaction required oxygen and produced hydrogen peroxide, was not stimulated by either NADP or FAD, and was inhibited by EDTA and iodoacetate. Physiologically-relevant inhibitors included gibberellic acid, indoleacetic acid and indoleacetaldehyde, though at higher than physiological concentrations. IEt oxidase from t he Farden Losa cultivar differed in some properties, but an antiserum prepared against this enzyme detected corresponding proteins from the Labrador and Tendergreen cultivars. In developing Tendergreen bean see ds, the IEt oxidase activity was temporally correlated with IEt levels . Parallel immunochemical measurement of IEt was obscured by non-speci fic reactions.