182 Essays in Biochemistry 



quenne 37 years later. Bouveault pointed out that theoretically nine 

 stereoisomers of inositol could exist, two of which would be optical 

 enantiomorphs. Four of these isomers are known to occur in nature. 

 Scherer's muscle sugar, now called mT/o-inositol, an ubiquitous cell 

 component, has been recognized as a growth factor for certain yeasts 

 and molds and as a vitamin necessary for the health of rats and mice. 

 Scyllitol, originally discovered in the organs of fish, occurs in trees and 

 in human urine. D-inositol and L-inositol are found as monomethyl 

 ethers in a variety of plants. Similarly, two of the sixteen possible 

 stereoisomer^ deoxyinositols have been isolated from plants. Of the 

 remaining inositols, four have been synthesized, so that at present only 

 one of the nine isomers remains unknown. The configurations of the 

 inositols (Fig. 1) were determined by Posternak and by Dangschat 

 and Fischer through the conversion of derivatives of the inositols to 

 known saccharic acids. 



The studies described here were begun in collaboration with Dr. 

 Erwin Chargaff at the Department of Biochemistry, Columbia Univer- 

 sity, in 1946 and have their origin in the observation of Kluyver and 

 Boezaardt 3 that Acetobacter suboxydans oxidizes mi/o-inositol (II) to 

 a monoketone, subsequently identified by Posternak as 2-keto-myo- 

 inositol (X). 4 



H,0, 



A. suboxydans 



The microorganism had thus singled out the central one of the three 

 vicinal as-hydroxyl groups of M7/o-inositol for oxidation. The ability 

 of A. suboxydans to carry out partial oxidations of polyhydroxy com- 

 pounds to monoketones had long been known to be subject to certain 

 steric limitations, which were formulated by Bertrand and by Hudson 

 as the following rule: Only a secondary hydroxyl group located be- 

 tween a primary hydroxyl group and another secondary hydroxyl group 

 in cis position is oxidized. 



However, since this rule could obviously not be applied to cyclic 

 compounds, it seemed of interest to study the specificity of the enzy- 

 matic attack of A. suboxydans on the hydroxyl groups of cyclitols, par- 

 ticularly as the rigidity of these cyclohexane derivatives, owing to the 



