Chemical System for Oxidation of lAA by Peroxidase 215 



peaks in the H0O2/H+ system, a new maximum appears at 297 ni/x. 

 In the peroxidase system, on the other hand, the maximum is at 285 

 m^. For a given quantity of substrate, the peaks at 248 and 254 m^u, 

 attain higher absorbancies in the peroxidase system than in the 

 H0O2/H+ system. 



More marked are the differences between the spectra during the 

 course of the reaction, as shown in Figures 1 and 2. The appearance 

 of the peak at 254 m/x is almost instantaneous in the peroxide system, 

 but much slower in the enzyme system, a clear separation showing 

 only after 45 min. Although the peak at 254 does not appear as quickly 

 in the peroxidase system, the general increase in absorption in the 

 240 to 260 mjx region is more rapid, so that the absorbancy of the en- 

 zyme system soon surpasses that of the peroxide system. In the indole 

 region of the spectrum absorbancy falls off rapidly during the first 

 hour in the enzyme system. The decrease is much slower in the per- 

 oxide system. These differences in the changing spectra of the two 

 systems indicate that the final products, though similar, are formed 

 by different mechanisms, as might be expected. The difference in the 

 specificities of the two systems has already been pointed out. 



Future work will be devoted to elucidation of the chemistry of 

 the H0O2/H+ system, which may enable us to predict the probable 

 structure of the product or products of the reaction. It is hoped that 

 this knowledge will permit us to select the proper conditions for iso- 

 lation of the products and for their synthesis. 



LITERATURE CITED 



1. Bauer, K., and Andersag, H. ^-Indolylacetic acids. U. S. Pat., 2,222,344. Nov. 

 19, 1941; Chem. Abst. 35: 1807*. 1941. 



2. Dalgliesh, C. E., and Kelly, W. Direct oxidation of indoles to oxindoles. Jour. 

 Chem. Soc. 3726, 3727. 1958. 



3. Freter, K., Axehod, J., and Witkop, B. Studies on the chemical and enzymatic 

 oxidation of lysergic acid diethylamide. Jour. Amer. Chem. Soc. 79: 3191-3193. 

 1957. 



4. Julian, P. L., Meyer, E. \V., and Printy, H. C. The chemistry of indoles. In: 

 R. C. Elderfield (ed.). Heterocyclic Compounds 3: 1-274. John Wiley and 

 Sons, Inc., New York. 1952. 



5. Kissman, H. M., Farnsworth, D. W., and Witkop, B. Fischer indole synthesis 

 with polyphosphoric acid. Jour. Amer. Chem. Soc. 74: 3948, 3949. 1952. 



6. Leonard, N. J., and Gash, V. W. Unsaturated amines. I. Determination of 

 the proximity of nitrogen to a double bond by infrared absorption spectra. 

 Jour. Amer. Chem. Soc. 76: 2781-2784. 1954. 



7. Manning, D. T., and Galston, A. W. On the nature of the enzymatically cata- 

 lyzed oxidation products of indoleacetic acid. Plant Physiol. 30: 225-231. 1955. 



8. Ray, P. M. The destruction of indoleacetic acid. II. Spectrophotometric study 

 of the enzymatic reaction. Arch. Biochem. Biophys. 64: 193-216. 1956. 



9. . Destruction of auxin. Ann. Rev. Plant Physiol. 9: 81-118. 1958. 



10. , and Thimann, K. V. The destruction of indoleacetic acid. I. Action 



of an enzyme from Omphalia flainda. .'Vrch. Biochem. Biophys. 64: 175-192. 

 of an enzyme from Omphalia flavida. Arch. Biochem. Biophys. 64: 175-192. 



