CATALYSIS AND THE ENZYMES 



such as the decomposition of esters are reversible, 

 and it only depends upon the conditions of the 

 experiment where the position of the state of 

 equilibrium is found : nearer to the ester or nearer 

 to the products of decomposition. Analysis and 

 synthesis are always connected. If a catalysing 

 influence acts on such reactions, it must accelerate 

 as well combination as decomposition. Else the 

 process would not agree with the fundamental 

 law of conservation of energy. We see that even 

 enzymes which catalyse a hydrolytic decomposi- 

 tion must act even in ..the contrary direction, as a 

 synthetical power. It was Van 't Hoff who first 

 stated this postulate. A short time afterwards 

 A. Croft Hill published his paper on the synthesis 

 of malt sugar by means of maltase, which had 

 hitherto been known only as a hydrolytic agent. 

 When maltase was made to act on a very concen- 

 trated solution of grape sugar, it was noticed 

 that a considerable quantity of a compound sugar 

 was formed from glucose. It is true that later on 

 it was shown that this sugar is not identical with 

 maltose, but consists chiefly of isomaltose, a closely 

 related sugar. Armstrong then showed that a 

 real synthesis of maltose can be made by means of 

 another enzyme, Emulsin, from grape sugar. 

 Emulsin is further effective on the synthesis of 

 the characteristic substance of bitter almonds, 

 amygdalin. When amygdalin is treated with 

 invertase, the cane - sugar - decomposing enzyme 

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