OXIDIZING ENZYMES 81 



bonate, and which was shown by Musculus to be present in the dead 

 cells of Micrococcus urece which develops in putrid urine. Zymase 

 was obtained by Biichner through the pressing of the ground yeast 

 cells, as has been described. This same method was later applied 

 to the lactic acid bacteria and the lactacidase obtained. 



Oxidizing Enzymes. The most typical example of an oxidizing 

 enzyme is the vinegar oxidase, the action of which is fairly well 

 known. The reaction may be written in the simple form 



CH 3 CH 2 OH + O 2 CHsCOOH + H 2 O. 



Since, however, many side reactions may occur, the bacterial oxida- 

 tion of alcohol is not in reality capable of so simple an expression. 



Reducing enzymes are the most common of ferments. They are 

 formed by practically all plants and animals and contained by all 

 but a very few bacteria, Strept. lacticus being one of the few excep- 

 tions. In this case the absence of the enzyme is used as a diagnostic 

 test for the organism. One of the most important reductases is 

 the peroxidase which reduces hydrogen peroxid to water with the 

 liberation of oxygen. 



2H 2 O 2 + peroxidase = 2H 2 O + O 2 . 



Others which reduce nitrates to nitrites of particular interest to 

 students of agriculture are 



2KNO 3 = 2KNO 2 + O 2 . 



Or at times they may reduce the nitrite to elementary nitrogen: 



z = 2CaO + 2N 2 + 5O 2 . 



Under appropriate conditions the important element, nitrogen, 

 may thus be lost from the soil by denitrification. In a similar way 

 sulphates are reduced to hydrogen sulphid: 



H 2 SO 4 = H 2 S + 2O 2 . 



REFERENCES. 



Bayliss: The Nature of Enzyme Action. 

 Euler: General Chemistry of the Enzymes, 

 Falk: The Chemistry of Enzyme Actions. 

 Robertson: The Physical Chemistry of the Proteins. 



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