516 



Dr. E. F. Armstrong. 



[Apr. 5, 



goes change about 1*3 times as rapidly as milk sugar. It is scarcely 

 possible to doubt that even greater differences exist both in the 

 affinity of the enzymes for the sugar and in the degrees of readiness 

 with which the enzyme sugar systems break down than are known 

 to hold in the case of acid sugar systems. It is important to keep 

 these considerations in view in discussing the rate at which different 

 enzymes effect hydrolysis. 



It will be apparent from what has been said that there is no reason 

 to suppose that the action of enzymes follows any other than a 

 normal course ; the difficulties which have been met with in inter- 

 preting such changes may be ascribed to the incomplete consideration 

 of the numerous factors involved. 



[D 1810, 8010; Q 1230.] 



" Studies on Enzyme Action. III. — The Influence of the Products 

 of Change on the Eate of Change conditioned by Sucroclastic 

 Enzymes." By Edward Frankland Armstrong, Ph.D., 

 Salters' Company's Besearch Fellow, Chemical Department, 

 City and Guilds of London Institute, Central Technical 

 College. Communicated by Professor H. E Armstrong, 

 F.B.S. Beceived April 5,— Bead April 28, 1904. 



D 1810 Hexoses — power of sucroclastic enzymes to combine with. 

 D 8010 Enzymes — activity of correlated with configuration of hydrolyte. 

 D 8010 V Emulsin, lactase, maltase — varying influence of glucoses and 

 Q, 1240 J glucosides on their activity. 



In the previous paper, it has been shown that, in order to explain 

 the action of sucroclastic enzymes, it is necessary to assume not only 

 that the enzyme combines with the hydrolyte but that it is also more 

 or less affected by — and presumably combines with — the product of 

 change. 



At present there is but little information available bearing on 

 this latter contention. The experiments to be described have been 

 made with the object of ascertaining by direct observation whether and 

 to what extent the action of a given enzyme is affected by one or more 

 of the products formed under its influence. They establish very 

 clearly the existence of a close relationship between the configuration 

 of the hexose and the enzyme in those cases in which a retarding 

 influence is apparent : it is difficult to explain such a result except on 

 the assumption that the enzyme and hexose combine together in some 

 intimate manner. 



