61 



was present. Bach showed that in a mixture of catalase and 

 peroxidase the latter did not have an appreciable effect upon the 

 action of the catalase. As we shall see in discussing the role of 

 catalase in the cell, it is possible that it acts as a brake on the 

 processes carried on by the oxidases. 



In the catalytic decomposition of hydrogen peroxide into 

 water and oxygen there has long been a controversy in regard 

 to the nature of the oxygen evolved; that is, whether it is in the 

 active state or in the inactive molecular condition. Now, in the 

 case of catalase we know from the results of Shaffer and others, 

 that no active oxygen is formed in the process, because guaiacum 

 is not blued, and none of the reactions of nascent oxygen are shown ; 

 and furthermore, as Shaffer pointed out, if catalase produced 

 active oxygen in the living cell, the protoplasm would probably be 

 killed at once by this extremely active and destructive agent. 

 How are we to harmonize those of the physico-chemical measure- 

 ments with the results of Shaffer, Liebermann and others? 

 From the physico-chemical data, the oxygen is in an atomic 

 state, while from tests on the reaction mixture, it is apparently 

 in a molecular state! We may say that the greater weight of 

 evidence seems to favor the idea that the oxygen is in the inactive 

 state and not capable of oxidizing directly. 



In concluding this short discussion of catalase, we are forced 

 to admit that our knowledge of this subject is very imperfect, 

 and Cohnheim^^ voiced the thoughts of many investigators when 

 he said: "It may well be that catalase is not an enzyme at all, 

 but that the catalytic decomposition of hydrogen peroxide is a 

 function of the large surfaces exposed by colloidal molecules, 

 whether of organized matter or of metals in colloidal solution, 

 the 'inorganic ferments' of Bredig. "^^ 



Laboratory of Biological Chemistry of Columbia University, 

 College of Physicians and Surgeons, New York. 

 {To he continued) 



2« Cohnheim. Lecture at the New York University and Bellevue Hospital 

 Medical College, New York City, December lo, 1909. 

 ^Bredig. Die Anorganische Fermente, 1901. 



