1904.] 



Studies on Enzyme Action. 



525 



Writing the skeleton formulas of the two compounds side by side, 

 it would seem that they differ but slightly in configuration, the 

 alteration being one which only concerns the ring structure. 



Ha 



RO 



Grlucoside. 



Galactoside. 



Assuming that the attachment of the enzyme is in some way 

 dependent on the hydroxyl groups, assuming also that the enzyme 

 is provided with points of attachment which bring it into relation 

 with the hydroxyl groups rather than with the oxygen atom in the 

 ring, it may be supposed that the alteration in the configuration of 

 the ring which is involved in the passage from glucose to galactose — 

 following the establishment of a /3- instead of an a-linkage in the 

 ring — would be of less consequence than any shifting of the hydroxyl 

 groups relatively to the ring plane. It is proposed to discuss the 

 question of the relation of glucose to galactose more fully in a separate 

 communication dealing with the relative stability of derivatives of 

 the two compounds in presence of acids. 



It remains only to consider why fructose, which is so closely related 

 to glucose, should have no inhibiting influence except on invertase. 

 Inasmuch as this enzyme is the only one at present known to us 

 which can effect the separation of fructose from higher carbohydrates 

 and inasmuch as it is influenced by fructose alone, it must be supposed 

 that the structure of invertase is in close correlation with that of 

 fructose. Assuming that fructose is also a y-oxide, its structure is 

 essentially different from that of glucose, as will be seen on comparing 

 their formulas. 



RO 



RO 



Grlucose. 



\ / 



Fructose. 



