ENZYMES AND THEIR ACTION 

 CLASSIFICATION OF ENZYMES. Continued 



;Fats. 



Lipases 



1. Autolytic Animal tissues 



2. Pancreatic Pancreatic juice 



(steapsin) 



3. Vegetable Castor bean, etc Fats Fatty acid and glycerol. 



Fats Fatty acid and glycerol 



Fats Fatty acid and glycerol. 



Nucleuses " 



1. Nucleicacidase. . Intestinal mucosa and juice, 



; other tissues. 



2. Nucleotidase. . . Intestinal mucosa and juice, 



; other tissues. 



3. Nucleosidase. . . Tissues 



i Nucleic acid and derivatives; 

 Nucleic acid Nucleotides. 



Nucleotides Phosphoric acid and nu- 



i cleosides. 

 Nucleosides '- Carbohydrate and bases. 



Oxidases, 



1. Catalase Plant and animal tissues. . 



2. Laccase Lac tree, fungi, etc 



3. Peroxidase , Plant and animal tissues. 



Hydrogen peroxide Oxygen or oxidation prod- 

 ucts. 



|Polyhydric para-phenols as Oxidation products. 

 ' hydroquinol and pyro-i 



Organic peroxides Oxygen or oxidation prod- 

 ucts. 



In text-book discussions of the enzymes it is customary to say that 

 very little is known regarding the chemical characteristics of these sub- 

 stances since no member of the enzyme group has, up to the present 

 time, been prepared in an absolutely pure condition. Apparently, how- 

 ever, from the nature of the facts in the case, it would be much more 

 accurate to say that we absolutely do not know whether a specific enzyme 

 has, or has not, been prepared in a pure state. (Some authors, like 

 Arthus, have assumed that enzymes are not chemical individuals, but 

 properties conferred upon bodies?) The enzymes are very difficult to 

 prepare in anything like a condition approximating purity, since they 

 are very prone to change their nature during the process by which the 



