Chromatographic Investigations of Indole Compounds 93 



our including quite a considerable amount of the unchanged com- 

 pounds in the extract. 



Dr. Andreae: Whenever we applied the material to our chroma- 

 tograms we used aliquots not exceeding 3 g. Did you ever get the 



amide? 



Dr. Wightman: No, we found no evidence at all on our chroma- 

 tograms for the formation of indole-3-acetamide in wheat tissue. This 

 may be due to the fact that we did not use sufficient tissue in our 

 treatments to produce enough indole-3-acetamide to give a color re- 

 action on the chromatogram when sprayed with Ehrlich's reagent or 

 a peak of activity in the bioassay. Certainly this amide is not as sen- 

 sitive to Ehrlich's as many of the other indole compounds used in 

 this investigation and is only active at fairly high concentrations in 

 the wheat cylinder bioassay technique. Our results, therefore, do not 

 preclude the possibility that indole-3-acetamide is formed during the 

 metabolism of lAA in wheat tissue, but they do indicate that it is 

 certainly not formed to any appreciable extent. 



Dr. Thimann: We can confirm that too, because our work on 

 barley tissue and also with the extracted enzyme shows not only that 

 the amide is not formed in any appreciable amount but that if it 

 were formed it is not acted on by the enzyme at any appreciable rate. 



Dr. Wain: I think the most important thing that Dr. Wightman 

 has mentioned is this conversion of the CHoCN group to COOH, 

 which is quite a new reaction. As he said, this is an alpha-oxidation 

 of nitrile and involves the breaking of a carbon carbon bond with the 

 loss of one carbon fragment. It's not strictly analogous to the break- 

 down of the cyanhydrin, as for example, the ones produced from glyco- 

 sides. Recently we have shown that you can take cell-free extracts from 

 pea tissue and effect alpha-oxidation of nitriles very readily. Here is 

 the same type of breakdown which occurs in the animal since com- 

 pounds like p-chlorobenzylnitrile fed to dogs are excreted as deriva- 

 tives of p-chlorobenzoic acid. 



Dr. Jepson: We must not forget that the whole of this indole 

 story as related to plants sprang from investigations that weren't 

 really on plants at all, but on human beings - the indole-3-acetic acid 

 isolated by Kogl and Haagensmit from the urine of their laboratory 

 assistant came not from the plants he ate but from the metabolism of 

 his dietary tryptophan. I want to suggest that further information 

 on plant indoles may well be obtained from studies of indoles ob- 

 tained directly from animals, though of course in general they come 

 initially from plants via tryptophan. For example, one is able to find in 

 human urine two of the compounds that Dr. Wightman wanted to 



