VII] OXIDIZING ENZYMES 115 



dases, so that some modification would be necessary to fit the case of 

 plants containing' peroxidases only. 



It should be mentioned that the aromatic substances which become 

 oxidized are frequently present in the plant as glucosides, that is, some 

 of the hydroxyl groups are replaced by sugar. Indoxyl, the precursor of 

 indigo, forms a good example, as it is present in the plant as a colourless 

 glucoside, indican (see p. 152). It is probably only after the hydrolysis 

 of the glucosides that the aromatic substances can become oxidized. 



REFERENCES 

 Books 



1. Chodat, R. Darstellung von Oxydasen undKatalasen tierischer und pflanz- 

 licher Herkuiift. Methoden ihrer Anwendung. Handbuch der biochemischen 

 Arbeitsniethoden. E. Abderhaldcn, Berlin, 1910, Vol. 3 (1), pp. 42-74. 



2. Perkin, A. G., and Everest, A. B. The Natural Organic Colouring 

 Matters. London, 1918. 



3. Wheldale, M. The Anthocyanin Pigments of Plants. Cambridge, 1916. 



Papers 



4. Clark, B. D. The Nature and Function of the Plant Oxidases. Toireya, 

 1911, Vol. 11, pp. 23-31, 55-61, 84-92, 101-110. 



5. Combes, R. Sur la presence, dans des feuilles et dans des fleurs ne formant 

 pas d'anthocyane, de pigments jaunes pouvant etre transformes en anthocyane. 

 C. R. Acad. SCI., 1914, Vol. 158, pp. 272-274. 



6. Everest, A. E. The Production of Anthocyanins and Anthocyanidins. 

 Part III. Proc. R. Soc, 1918, B Vol. 90, pp. 251-265. 



7. Ewart, A. J. A Comparative Study of Oxidation by Catalysts of Organic 

 and Inorganic Origin. Proc. R. Soc, 1915, B Vol. 88, pp. 284-320. 



8. Fischer, E., und Preudenberg, K. Ueber das Tannin und die Synthese 

 ahnlicher Stofte. Ber. D. chem. Ges., 1912, Vol. 45, pp. 915-935. 



9. Keeble, P., and Armstrong, E. P. The Role of Oxydases in the Forma- 

 tion of the Anthocyan Pigments of Plants. J. Oenetics, 1913, Vol. 2, pp. 277-311. 



10. Moore, B., and Whitley, E. The Properties and Classification of the 

 Oxidising Enzymes, and Analogies between Enzymic Activity and the Effects of 

 immune Bodies and Complements. Biochem. J., 1909, Vol. 4, pp. 136-167. 



11. Onslow, M. Wheldale. Oxidising Enzymes. I. The Nature of the 

 " Peroxide " naturally associated with certain direct Oxidising Systems in Plants. 

 Biochem. J., 1919, Vol. 13, pp. 1-9. 



12. Palladin, W. Das Blut der Pflanzen. Ber. I), hot. Ges., 1908, Vol. 26 (/, 

 pp. 125-132. 



13. Palladin, W. Die Verbreitung der Atmungschromogene bei den Pflanzen. 

 Ber. D. hot. Ges., 1908, Vol. 26 o, pp. 378-389. 



14. Palladin, W. Ueber die Bildung der Atmungschromogene in den Pflanzen 

 Ber. D. hot. Ges., 1908, Vol. 26 a, pp. 389-394. 



8—2 



