CATALYSIS AND THE ENZYMES 



sugar by diluted sulphuric acid, are reactions of the 

 first order. In every moment of the reaction 

 its velocity is directly proportional to the quantity 

 of the substance yet unchanged, and directly 

 proportional to the concentration of the acid. 



Quite similar ratios were found in enzyme 

 chemistry. The cane-sugar-splitting enzyme of 

 yeast, called Invertase, and Amylase or the starch- 

 dissolving agent in seeds, act in the same way. Be- 

 tween certain extreme limits the effect is directly 

 proportional to the concentration of the enzyme. 

 So it is possible to calculate the quantity of 

 invertase or of amylase in a solution, when a 

 standard solution of the same enzyme is used. 

 Pepsin of the stomach showed a different result. 

 In Prague, in 1885, Schutz discovered that the 

 amount of protein digested in a certain time 

 is not proportional to the quantity of the enzyme 

 itself, but proportional to the square root of the 

 quantity of the enzyme. This rule has often been 

 confirmed. But it was only a couple of years ago 

 that Arrhenius, of Stockholm, explained this 

 remarkable law. If we consider that the deter- 

 mination of the enzyme effects is made in the 

 first stage of the enzyme action, we may assume 

 that the quantity of the transformed albumin 

 is very small in comparison with the quantity 

 of the albumin not yet decomposed. We can 

 therefore suppose that at the beginning of the 

 reaction the quantity yet unaltered is constant. 

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