Metabolism of indole derivatives 



shows extensive conversion of the amide to lAA, a small production of 

 ICA from the nitrile with apparently no formation of lAA, and as with all 

 other tissues so far employed, a considerable conversion of the methyl ester to 

 the acid. These conclusions are supported in the main by the results in the 

 wheat cylinder test {Figure 14) and in the pea test {Figure 17). The bio-assay 

 of the IAN chromatogram, however, showed activity at Rf 0- 1-0-2, which 

 suggests that a small amount of lAA is formed from the nitrile. 



Rf values 

 0-0-1 0-1-0-Z 0-2-0-3 0-3-0'i Of -0-5 OS-OS 0-6-0-7 0-7-0-8 0-8-0-3 O-S-1-0 



Wafer 



lAA 



I A Am 



IAN 



lAMe 



Y V T T ^ X Y- T T T^ 

 YY^TTYYYYY 



YTTTTYv-rrr 



YTYY-YY-TY-rx 



Y T Y Y Y Y Y_Y t^ Y 



Y r 



V Y 



X Y Y Y Y 

 Y ^ Y Y Y 

 1 Y Y Y -r 



Y Y 



Y Y 

 -r Y 



Y X Y Y Y Y Y ^ Y. Y 



~r Y Y Y Y t "t T ^ X 



-Y } TT^YYYYY 



Y T J "Y- Y T Y nr T T 



Y T |-rYYYYrT 



Solutions treated ^vith maize tissue 



Figure 17. Bio-assay of chromatogram of extracts from maize-treated solutions usirig the pea curvature 

 test. 



DISCUSSION 



The present series of results indicate that the activities of lAAm, IAN, and 

 lAMe in the wheat cylinder and pea curvature tests are related to their 

 hydrolysis to lAA within the tissues of the test material. The conversion of 

 IAN to lAA by oat coleoptile tissue has been previously reported by Bentley 

 and Housley (1952) and by Thimann (1953), although, as was shown by 

 Jones et al. (1952), the amount of acid produced is quite small in relation to 

 the activity of the nitrile. Wheat tissue seems to behave in essentially the 

 same manner as oat tissue, though in this instance the amount of acid 

 produced appears to be fairly substantial (see Figure 4). The inactivity of 

 IAN in the pea test is explicable from the present results, which show no 

 evidence of the production of lAA when solutions of the nitrile were exposed 

 to pea stem tissue. This result was also found by Thimann (1953), who 

 further reported that IAN showed slight growth-promoting activity in the 

 split maize coleoptile test. The slight conversion of IAN to lAA by maize 

 tissue shown in this investigation {Figure 14) would seem to confirm Thimann's 

 result. 



The amide has been suggested as a possible intermediate in the conversion 

 of IAN to lAA (Bentley and Housley, 1952; Jones et al., 1952), although it 



245 



17 



