ENZYMES AND THEIR ACTION 

 CLASSIFICATION OF ENZYMES. Continued 



Name and Class 



Lipases 



1 . Autoly tic 



2. Pancreatic 



(steapsin) 



3. Vegetable 



Distribution 



Animal tissues.. . 

 Pancreatic juice. 



Castor bean, etc. 



Substrate 



End-products 



Nucleuses 



1. Nucleicacidase. 



2. Nucleotidase.. . 



3. Nucleosidase.. . 



; Fats 



Fats Fatty acid and glycerol. 



Fats Fatty acid and glycerol. 



i Fatty acid and glycerol. 



Fats. 



Intestinal mucosa and juice, 



other tissues. 

 Intestinal mucosa and juice, 



other tissues. 

 Tissues 



Nucleic acid and derivatives. 



Nucleic acid Nucleotides. 



Nucleotides. . 

 Nucleosides. . 



Oxidases. 

 i. Laccase.. 



2. Peroxidase. 



3. Catalase. . . 



4. Purine-oxidases. 



(a) Hypoxanthine Animal tissues., 

 oxidase. 



(b) Uricase Animal tissues.. 



(c) Xanthine Animal tissues, 

 oxidase. 



Lac tree, fungi, etc , 



. Plant and animal tissues. 

 . Plant and animal tissues. 



. . . Phosphoric acid and nu- 



cleosides. 

 . . . Carbohydrate and bases. 



Polyhydric para-phenols as Oxidation products. 



hydroquinol and pyro- 

 l gallol. 



. Organic peroxides Oxygen or oxidation prod- 

 ucts. 



, Hydrogen peroxide Oxygen or oxidation prod- 

 ucts. 

 Purines. 

 . Hypoxanthine Xanthine. 



Uric acid ' JAllantoin. 



Xanthine . iUric acid. 



(acid-protease) 



3. Trypsin Pancreatic juice. 



(alkali-protease) 



4. Vegetable pro- 

 teases. 



(a) Bromelin Pineapple 



(b) Papain Pawpaw 



(papayotin) 



Purinases(see Purine 

 Oxidases and Pur- 

 ine Deaminases). 



Proteins.. . . 



Proteins.. 

 Proteins.. 



peptides. 

 Proteoses, peptones, pep- 

 tides, amino-acids. 



Proteoses, peptones, etc. 

 Proteoses, peptones, etc. 



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 



