CHAPTER XII. 

 ENZYMES. 



FOR more detailed study we recommend the following books of reference: 

 "The Nature of Enzyme Action," by W. M. BAYLISS; "Allgem. Chemie der 

 Enzyme," by H. EULER (J. F. BERGMANN, Wiesbaden, 1910); "Die Fermente 

 und ihre Wirkungen," by C. OPPENHEIMER (F. C. W. VOGEL, Leipzig, 1913); 

 [" Biochemical Catalysis in Life and Industry," by JEAN EFFRONT. Translated 

 by SAMUEL PRESCOTT. JOHN WILEY & SONS, INC., 1917. Tr.] 



L/ist of the best known enzymes. 



Amylase hydrolyzes starches and glycogen into dextrin and maltose. 



Catalase decomposes peroxid of hydrogen. 



Chymosin is rennin. 



Diastase fluidifies starches and hydrolyzes them to maltose. 



Emulsin hydrolyzes glucosides. 



Erepsin hydrolyzes albumoses and peptones to amino-acids. 



Fibrin-ferment an hypothetical ferment which coagulates fibrin. 



Invertase hydrolyzes cane sugar. 



Lipase hydrolyzes fats into fatty acids and glycerin. 



Maltase cleaves glucosides. 



Oxidase an oxygen carrier. 



Pancreatin from the pancreatic juice is a mixture of several enzymes. 



Papain hydrolyzes albumin. 



Pepsin hydrolyzes albumin in acid solution. 



Ptyalin is the amylase of the saliva. 



Rennin coagulates milk. 



Steapsin is lipase. 



Trypsin hydrolyzes albumin in alkaline solution. 



Tyrosinase oxidizes tyrosin and some of its derivatives. 



Zymase splits sugar into alcohol and CO 2 . 



To split complex molecules, chemists have to employ powerful re- 

 agents, such as acids, alkalis, etc. They smash, as it were, the 

 clockwork with a hammer and then pick out the undamaged particles. 

 Just as a watchmaker employs for each screw a suitable tool or a 

 specially made pliers, so nature has constructed delicate instruments 

 for this purpose. Enzymes are such tools for the chemical break- 

 ing down or building up of molecules. Albumin, carbohydrates and 

 fats may all be split up by acids. For each purpose nature has a 

 special enzyme, or even several; for the cleavage of albumin, pepsin 

 and trypsin; for starches, diastase; for fats, lipase. 



We shall see that some enzymes are fashioned exactly for their 

 use, so that the simile of EMIL FISCHER, which compares the enzyme 



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