OXIDATION ENZYMES. 13 



WIENER, SCHITTENHELM, and BURIAN/ of transforming xan thine and 

 bypoxanthine into uric acid by oxidation. 



Like other enzymes in general the so-called oxidation enzymes show 

 from the above a more or less pronounced specificity, as a certain oxida- 

 tion enzyme acts only upon certain substances and does not oxidize 

 others. This behavior, which is difficult of reconciliation, that these 

 enzymes act as oxygen -carriers, indicate that in the oxidation the active 

 substances do not act upon the oxygen, but rather upon the substance 

 to be oxidized. We cannot at present give any statement as to the 

 extent of action of the oxidation enzymes in the oxidations of the ani- 

 mal body, and it is still a question whether we were actually dealing 

 with enzymes in all cases where oxidation enzymes have been claimed 

 to have been found. 



In investigations with hydroperoxides and vegetable peroxidases BACH 

 and CHODAT 2 found that peroxides and peroxidases always tpok part 

 in the reaction in constant proportions, and that the peroxidases were 

 quickly used up, which certainly does not indicate that these bodies 

 have an enzymotic nature. Aso 3 has also shown that in certain cases 

 where an apparent oxidase action was present, we were very probably 

 dealing only with nitrites which were present; and finally, attention 

 must be called to the fact that manganese or iron, sometimes in consider- 

 able amounts, has been found in many oxidases. As manganous and 

 ferrous salts are active as catalyts in certain other oxidations, so also 

 in certain cases important roles as oxygen-carriers have been ascribed 

 to these metals, for instance in laccase, which contains manganese (BER- 

 TRAND), and the oxidases containing iron (SPITZER'S nucleoprotein) . 

 MANCHOT 4 by his work on the autooxidation of ferrous sulphate has 

 called attention to the apparently great importance of iron for physio- 

 logical oxidations, and recently several investigators as TRILLAT, DONY- 

 HENAULT and J. WOLFF, have shown that several oxidase actions can be 

 brought about by colloidal inorganic catalyts or by mixtures of these 

 with organic colloids. Finally EULER and BOLIN 5 have shown that the 

 lucerne-laccase is not an enzyme at all, but that its action is due to the 

 presence of salts of organic acids. The question as to the nature of the 

 so-called oxidation enzymes surely requires a thorough investigation. 



The assumption of special-oxidation enzymes does not at least give 



1 Spitzer, Pfluger's Archiv, 56; Wiener, Arch. f. exp. Path. u. Pharm., 42; Schit- 

 tenhelm, Zeitschr. f . physiol. Chem., 42 and 43 ; Burian, ibid., 43. 



2 Ber. d. d. chem. Gesellsch., 37. 



3 Beihefte zum botan. Centralbl., 18. 



4 Zeitschr. f. anorg. Chem., 2". 



5 Trillat, Compt. rend., 137 and 138; Dony-He*nault. Bull. Acad. Roy. Belg. 1908; 

 J. Wolff, Compt. rend., 146; H. Euler and J. Bolin, Zeitschr. f. physiol. Chem., 57. 



