A. A. BITANCOURT 

 ALEXANDRA P. NOGUEIRA 

 KAETHE SCHWARZ 



Plant Cancer Research Center, 

 Institute Biologico, Sao Paulo, Brazil 



Pathways of DecomposltLon (CataboUc Lattice) 



of Indole Derivatives 



Plant tumors induced by Agrobacterium tiimefaciens usually have a 

 higher content of free auxin than the corresponding normal tissue 

 (4, 13, 16, 17). This may be due to increased auxin synthesis in tumors 

 or more active auxin destruction in the corresponding normal tissue 

 (3). The formation and destruction of auxins in general, and of in- 

 dole-3-acetic acid in particular, have therefore an important bearing 

 on the etiology of plant cancer and in 1954 we started a study of the 

 metabolism of indole derivatives (30). We soon noticed that destruc- 

 tion of indole substrates occurred in our blanks as well as during 

 extraction and chromatographic procedures, due to spontaneous de- 

 composition. We concluded that a knowledge of the spontaneous 

 process was necessary for the interpretation of metabolic studies. 

 Since 1956 we have studied the spontaneous or induced decomposi- 

 tion, by ultraviolet radiation, of 14 indole derivativesi, most of which 

 are involved in the classical scheme of indole metabolism (8, 11,20) 

 represented in the central part of the diagram of Figure 1. 



^The follo^ving indole derivatives were used in these studies: tryptophan 

 (TRPH), 5-hydroxytryptophan (5-HTRPH), indole-3-pyruvic acid (IPA), trypta- 

 mine (TRAM), 5-hydroxytryptamine (5-HTRAM), indole-3-acetaldehyde (lAAL), 

 indole-3-acetic acid (lAA), 5-hydroxyindole-3-acetic acid (5-HIAA), N-hydroxyin- 

 dole-3-acetic acid (N-HIAA), indole-3-glycolic acid (IGCA). indole-3-glyoxylic acid 

 (IGXA), indole-3-aldehyde (lA), skatole (SK), and indole (IN). 



After the meetings in 1959, we were able to compare the sample of indole-3- 

 aldehyde used in these studies (Bios Laboratories, Inc.) with one purchased from 

 Aldrich Chemical Co., Inc. The two samples are obviously different, although both 

 are aldehvdic indole derivatives. The Aldrich sample is the only one that agrees 

 with the physical and chemical properties of indole-3-aldehyde reported m the 

 literature. It is therefore obvious that the substance mentioned under the initials 

 of lA in this paper is not indole-3-aldehyde, but it is possibly one of its hydroxy 

 derivatives. 



[181] 



