Metabolism of indole derivatives 



in the extract was prepared and it was shown that its melting point was 

 not depressed by admixture with the />-phenylphenacyl ester of indole-3- 

 carboxylic acid. The identity of the acid in the extract was therefore fully 

 established as indole-3-carboxylic acid. This same indole compound has 

 recently been found in pea tissue by Cartwright, Sykes, and Wain (1956). 



All these experiments then, strongly suggest that indole-3-carboxylic acid 

 is a product of indole-3-acetonitrile metabolism in some plant tissues. This 

 implies the loss of the — CN group and the oxidation of the a-carbon atom 

 of the side-chain, a biochemical 'a-oxidation' mechanism which parallels 

 that already suggested in an earlier paper of this volume (Fawcett el al., 1956) 

 to account for the activity of certain co-2:4-dichlorophenoxyaIkylnitriles in 

 the wheat cylinder test. 



REFERENCES 



Bentley, J. A., and Housley, S. (1952). Studies on plant growth hormones. I. 



Biological activities of 3-indolylacetaldehyde and 3-indolyIacetonitrile. J. exp. Bot. 



3, 393. 

 Cartwright, P. M., Sykes, J. T., and Wain, R. L. (1956). The distribution of 



natural auxins in germinating seeds and seedling plants. This volume, p. 32. 

 Fawcett, C. H., Taylor, H. F., Wain, R. L., and Wightman, F. (1956). The 



degradation of certain phenoxy acids, amides, and nitriles within plant tissues 



This volume, p. 187. 

 Jones, E. R. H., Henbest, H. B., Smith, G. F., and Bentley, J. A. (1952). 3-indolyl- 



acetonitrile: a naturally occurring plant growth hormone. Nature, 169, 485. 

 Stowe, B. B., and Thimann, K. V. (1954). The paper chromatography of indole 



compounds and some indole containing auxins of plant tissues. Arch. Biochem. 



Biophys. 51, 499. 

 Thimann, K. V. (1953). Hydrolysis of indoleacetonitrile in plants. Arch. Biochem. 



44, 242. 



247 



