714 THE BIOCHEMISTRY OF B VITAMINS 



Acetobacter suboxydans. 80 ' 87, 88, 89 According to Magasanik and Char- 

 gaff, 89 "only those hydroxyls are oxidized that are situated in a polar 

 plane." This would mean that in the case of meso-inositol only the cis- 

 hydroxyl in the 2 position is attacked. Schopfer 62 believed this hydroxyl 

 to be necessary for vitamin activity. If this is true, scyllo-ms-inosose, 

 which is active for Eremothecium ashbyii (Table 49), must be reduced 

 to the corresponding meso-inositol before it is utilized by the organism. 



Inhibitory Analogues of Inositol 



The theory was advanced by Slade 90 - 91 in 1945 that the powerful 

 insecticidal action of y-hexachlorocyclohexane ("Gammexane") could be 

 explained on the basis of its structural similarity to meso-inositol. He 

 assigned to the y-isomer the configuration corresponding to that of meso- 

 inositol and pointed out that this compound has a much higher toxicity 

 for insects than do the a-, B-, and S-isomers. It was proposed that the 

 y-isomer exerts its inhibitory action by blocking the functioning of 

 inositol in some important enzyme system. 



Recent x-ray studies 92 have indicated that the configuration of the 

 y-isomer does not correspond to that of meso-inositol; nevertheless, 

 Slade's theory concerning the antagonism between "Gammexane" and 

 meso-inositol stimulated several studies, and it was demonstrated that 

 in some cases the toxic action of y-hexachlorocyclohexane could be af- 

 fected by meso-inositol. 



Kirkwood and Philips 93 found that the Gebruder Mayer strain of 

 yeast, which normally requires 1 y of inositol per ml of medium for 

 maximal growth, was strongly inhibited by 60 y per ml of y-hexachloro- 

 cyclohexane. This inhibition was "progressively but not completely" 

 reversed by the addition of 1 to 6 y of meso-inositol per ml of medium. 

 This would correspond to a molar inhibition ratio of about 30. The a-, 

 B-, and 8-isomers of hexachlorocyclohexane also had a slight inhibitory 

 effect, but only the inhibition caused by the y-isomer could be reversed 

 by meso-inositol. 



The y-isomer of hexachlorocyclohexane completely inhibits the growth 

 of Nematospora gossypii, whereas the /3-isomer is inactive and the 

 a-isomer is only slightly inhibitory. 94 The inhibition caused by 10-60 y 

 per ml of the y-isomer was reduced to 50 per cent by the addition of 60 y 

 per ml of meso-inositol and to 6 per cent by 100 y per ml of the vitamin. 



Schopfer et al. 95 found that flavinogenesis is inhibited in Eremothecium 

 ashbyii var gossypii by y-hexachlorocyclohexane and that the growth 

 medium is completely decolorized. The effects of 800 y of the inhibitor 

 are prevented by the addition of 5 y of meso-inositol. Scyllo-ms-inosose 



