ENZYMATIC CONVERSION OF INDOLE ACETALDEHYDE AND NAPHTHALENE ACETALDEHYDE TO AUXINS

Abstract

Juice expressed from coleoptiles of Avena sativa is shown to contain an enzyme system capable of converting 1-naphthaleneacetaldehyde to 1-naphthalene acetic acid, yielding 1 mole of acid per 2 moles of aldehyde. Previous expts. showed that the arbitrary, biological unit of 1 [mu]g. -"equivalent" of indoleacetaldehyde yields about 28 x 10-9 moles of indoleacetic acid when treated with coleoptile juice. On the basis of the molar yield obtained with the naphthalene analogue it is concluded that the 28 x 10-9 moles of indoleacetic acid originated from 56 x 10-9 moles of indoleacetaldehyde. One [mu]g. -"equivalent" of indoleacetaldehyde, therefore, would be equal to 56 x 10-9 moles or approx. 9 [mu]g. Indole-, naphthalene-, and phenylacetaldehyde show activities in the Avena test which are 11, 6, and 7%, respectively, of those of the corresponding acids.