Pfizer Handbook of Microbial Metabolites 



82 



A somewhat similar aromatic ring cleavage has been proposed^ 

 in the biosynthesis of patulin. 



It is likely that the biosynthetic origins of the two recently re- 

 ported streptomycete antibiotics, acetomycin and 3-carboxy-2,4- 

 pentadienal lactol (PA-147) are mutually related. 



CH3 



I 



CH- 



CH 



CH3 



-C— CO— CH3 



I 



c=o 



CH3CO— o o 



Acetomycin 



CH= 



I 

 CH 



/ \ / 

 HO O 



C— CH=CH2 



c=o 



CH= 



=C— CH=CH2 



O 



3-Carboxy-2,4-pentadienal Lactol 



CH 



c=o 



HO 



The biosynthesis of ascorbic acid in Aspergillus niger is 

 known to involve the following stages:* 



000 



II , II II 



:ko c — c — c — 



— — 0= — c 



_ o^ o-^ II c 



COOH CH2OH CH2OH CHoOH 



D-Glucuronic L-Gulono- 2-Keto-L- L-Ascorbic 



Acid lactone gulonolactone Acid 



The glucuronic acid probably quite generally can arise from 

 glucose by a hexose interconversion of the type discussed earlier 

 in the section on sugars. In muscle tissue it may also come 

 from myoinositol. 



•■' J. D. Bu'Lock and A. J. Ryan, Proc. Chem. Soc, 222 (1958). 

 *K. Sivarama Sastry and P. S. Sarma, Nature 179 44 (1957). 



