THE CAKBOIIYJD1UTES AXD TIIEIK METABOLISM 223 



C \ 



I N H &&SSS 



*IICOII 



I 

 *HCOII 



I 



*HCOII 



I 

 *IICOH 



I p M 



CHoOH 



Accordingly there may be 2 4 or 1G possible aldohexoses. Largely through 

 the researches of Emil Fischer, 14 of these are now known, although only 

 three glucose, mannose, galactose occur naturally. These isoiners are 

 represented in Table II. 



TABLE II. ALDOHEXOSES 

 1. Manniiol Series 



' All sugars known as cl-sugars are not necessarily dextrorotatory, nor are all 

 1-sugars necessarily levorotatory. All compounds derived from d-glucose by reactions 

 that leave the stereochemical structure unchanged are designated d compounds, re- 

 gardless of their rotation, and similarly for I-forms. 



