1912.] Studies on the Reductase of Liver and Kidney. 489 



Time. 





32 N. KMn0 4 required by 10 c.c. 

 of the reaction mixture. 



: 



Amount of hydi 

 decom] 



ogen peroxide 

 osed. 









per cent. 









55-72 











5 





23 '91 



57 



1 



10 





12 -52 



77 



6 



15 





6-94 



87 



6 



20 





4-32 



92 



3 



25 





2-70 



95 



2 



35 





1-33 



97 



6 



45 





0-67 



98 



8 



70 





0-25 



99 



5 



With boiled press juice no decomposition of hydrogen peroxide occurred. 



In order to determine the action of proteins on hydrogen peroxide the rate 

 of decomposition of hydrogen peroxide, at 25° C, in a mixture containing 

 190 c.c. of 0-0950 molar peroxide solution and 5 c.c. of 15-per-cent. white-of- 

 egg solution was determined. The following table gives results obtained : — 



Time. 



-0332 N. KMn0 4 required by 10 c.c. 

 of the reaction mixture. 



Amount of hydrogen peroxide 

 decomposed. 







per cent. 



mi^s. 



55-72 



o-o 



5 



54 -72 



1-8 



10 



53 -84 



3-4 



15 



53 -84 



3-4 



30 



53 80 



3-4 



60 



53 -71 



3-6 



It will be seen from the results given in the foregoing tables that the 

 decomposition of hydrogen peroxide by the press juice of liver cannot be 

 attributed to the organic matter contained in the juice ; for in the first 

 experiment the amount of organic matter is extremely small, and in the 

 second, where the amount of organic matter is relatively large, only a small 

 amount of the hydrogen peroxide was found to have been decomposed, even 

 at the end of an hour. Since it has been observed by Spitzer* that the liver 

 is rich in catalase, it is most probable that the decomposition of hydrogen 

 peroxide by liver press juice is due to the presence of this enzyme. If, 

 however, the press juice contains a reducing endo-enzyme, as we suppose, it 

 is not improbable that the decomposition of the hydrogen peroxide may be 

 due to the combined action of the catalase and the reductase. 



(c) Experiments with Soluble Prussian Blue. — It has already been shown 



* Spitzer, ' Pfliiger's Archiv,' 1897, vol. 67. 



