CHAPTER X. 

 THE HYDROLYZING ENZYMES. 



GENERAL CHARACTERISTICS OF THE ENZYMES. 



Disaccharides in aqueous solution are hydrolyzed by mineral acids 

 in accordance with the equation: 



Ci2H 22 On + H 2 O = 2C 6 Hi2O6 



Any acid will act upon any disaccharide, but the intensity or Velocity 

 of Hydrolysis varies somewhat with the nature of the acid and of the 

 disaccharide. 



The law which connects the time and the extent of the hydrolysis 

 of cane-sugar by acids was first formulated by Wilhelmy in 1850, who 

 showed that at every instant the same percentage of the hitherto unchanged 

 sugar is hydrolyzed per second. Thus, if to begin with we have 100 

 parts of sugar, and of this 5 parts are hydrolyzed in a given interval 

 of time, we have now 95 parts of unchanged sugar left, and in the 

 succeeding interval five hundred ths of this will be hydrolyzed. The 

 transformation, therefore, proceeds in the following manner: 



Number of cane- Number of sugar- 



sugar molecules. molecules hydrolyzed. 



First interval of time . . . . . 100.00 T ^ 7 X 100.00 = 5.00 



Second interval of time . . . . . 95.00 Y^ X 95.00 = 4.75 



Third interval of time . . . . . 90.25 T fo X 90.25 = 4.51 



Fourth interval of time .... 85.74 T ^ X 85.74 = 4.29 



Fifth interval of time ..... 81.45 T fo X 81.45 = 4.07 



In other words, unit-mass of sugar, or one hundred molecules of 

 sugar, always decomposes at the same rate, no matter how much or 

 how little sugar, i.e., how many units or what fraction of a unit, is 

 present in the given solution at the moment. If a gram-molecule 

 of sugar be present, just the same percentage of sugar-molecules will be 

 undergoing transformation per second as when five gram-molecules 

 of sugar are present, but in the latter case the total amount of trans- 

 formation observed per second will be five times as great as in the 

 former. 



