64 



H 



\/ 

 C 



l\ 



GENERAL BIOCHEMISTRY 

 CH2OH H 



C O C O 



H \| 1/ H 



OH H 



H 



J 

 C 



OH 



H 



I / 

 C 



OH 



OH H 



-C 



CH.2OH 



\ I 

 C 



OH 



H OH 



a-D-glucose 



CHoOH 

 C O 



OH 



C 



H 



H 



OH H 



H 



\ I 

 G 



OH 



H 



I / 

 C 



H OH 



a-D-fructose 

 CH2OH 



c — o 



/I 



' H 



H 



\ I 



C 



c 



-G 



H 



OH 



a-D-galactose 



OH OH/1 

 OH\| 1/ OH 



G ^C 



H H 



a-D-maiinose 



Sucrose 



This (lisaccharide is also known as cane sugar, beet sugar, or sac- 

 charose. It is the most widely distributed in free form of all the sugars 

 of this group and occtns in most green plants. The best commercial 

 sources are the sugar cane, beet, palm, and maple and sorghum cane. 



Nectar of flowers is rich in sucrose and is the raw material for honey. 

 Bees concentrate the solution and hydrolyze the sucrose to a mixture 

 of glucose and fructose. Thus these two monosaccharides are com- 

 bined in sucrose with elimination of a molecule of water. Moreover, 

 the tests for reducing carbohydrates are negative with sucrose, in- 

 dicating that both potential carbonyl groups are involved in the acetal 

 linkage. Ghemical studies on sucrose show that the fructose portion is 



GH,OH 

 C O 



GH2OH 



H 



H 



1/ 

 G 



l\ 

 OH 



H 



OH 



\ I 

 G— 



H 



J 

 G 



O 



H 



H 



-G' 



I 

 OH 



H 



\ I 

 G- 



O 



OH 



l-a-D-glucosido-2-/3-D-fructose 



OH 



I /■ 

 -G 



H 



G 



GH2OH 



