405 Ppans and Related Substances 



The fungi are able to use pentose and triose substfates 

 as well as glucose, although labeling studies have shown 

 conversion of glucose to kojic acid without cleavage of 

 the 6-carbon chain. ^ 



Gluconoacetobacter liquefaciens seems to be more se- 

 lective in its substrate and uses only glucose, gluconate 

 and 2-ketogluconate. The variety of y-pyrones produced 

 is useful in deducing the kind of intermediate involved. 

 The foregoing considerations plus the isolation of 2,5- 

 diketogluconic acid from cultures of this bacterium have 

 led to formulation of the following biosynthetic route to 

 the pyrones produced by Gluconoacetobacter liquefaciens:'^ 



CH2OH CH2OH 



I I 



c — o c — o 



H /I \ H H /I \ 



1/ H \i -2H IX H \ +H2O 



c c > c c=o > 



|\ OH H /| |\ OH H 



HO \| 1/ OH HO \| 



c — c c — c 



II II 



H OH H OH 



Glucopyranose Gluconolactone 



CH2OH 



I 



C— OH 

 H yi OH 



IX H I -2H 



,C c=o 



^\\ OH 

 -2H HO \| 



C— 



I 



H O 

 2-Ketogluconic Acid 



H OH 

 Gluconic Acid 



H OH 

 5-Ketogluconic Acid 



1 H. R. V. Arnstein and R. Bentley, Biochem. J. 62 403 (1956). 

 ^ Ko Aida, Mitsuko Fujii and Toshinobu Asai, Bull. Agr. Chem. 

 Soc. (Japan) 21 30 (1957). 



