Metabolism of Inositol 187 



polar) and downwards (south polar).* Each carbon atom possesses 

 one equatorial and one polar bond and can therefore carry substituents 

 in either position. There are two possible chair forms, one being 

 formed from the other by a movement of the ring atoms through the 

 central plane which changes polar bonds to equatorials and vice versa. 



In substituted cyclohexanes, the substituent groups occupy preferen- 

 tially the equatorial positions in which more space is available than 

 in the crowded polar regions. Consequently, when the two chair forms 

 are not identical, the molecule will be found to exist in the conforma- 

 tion having the smallest number of polar substituents. 



On the basis of these considerations the conformations shown in 

 Fig. 3 could be assigned to the inositol isomers. It was reasonable to 

 expect that the susceptibility of the inositol molecule to chemical and 

 enzymatic attack would depend on the actual shape of the molecule 

 as shown by its conformation; and indeed, on correlation of the action 

 of A. suboxydans on the inositols with their conformations (Table 1), 



Table 1. The Action of A. suboxydans on Inositols and Their Deoxy 

 and Keto Derivatives 



* In meso compounds alternative numbering sequences are possible (see Fig. 1); for presentation in 

 this table these compounds have been numbered clockwise. 



a striking regularity became at once apparent: only polar hydroxyl 

 groups had been oxidized. 



*The use of the term "axial" instead of "polar" has been suggested to avoid 

 ambiguity (D. M. R. Barton et al., Science, 119, 49 (1954). 



