Pfizer Handbook of Microbial Metabolites 



54 



process is at present believed to be represented by the scheme : " 



Biotin 



C02 



CH3CO— S— CoA 

 ATP 



ADP 



COOH 



CH2— CO— S— CoA 

 Malonyl Coenzyme A 



CH3CO— S— CoA 



COOH 



CH3— CO— CH— CO— S— CoA + HS— CoA 



TPNH (4H®) 



several steps, 

 decarboxylase, hydrogenase 



CH3— CH2— CH,— CO— S— CoA + CO, + H,0 



The butyryl coenzyme A can then react with another molecule 

 of malonyl coenzyme A and the process repeats. There is a 

 statistical distribution peak at 14-18 carbon atom length chains. 

 Certain bacteria can couple chains of considerable length as, 

 for example, in corynomycolic acid produced by corynebacteria : 



CH3(CH>)u— CH 

 OH 



COOH 



I 

 CH— (CH,),3CH3 



Corynomycolic 

 Acid 



oxidative decarboxylation 



CH3(CH,)u— C— CH,— (CH,),3CH3 + CO. 



O 



This compound is formed by the coupling of two palmitic acid 

 molecules as shown by a labeling experiment.-" C^M-Labeled 



13 Salih J. Wakil, Edward B. Titchener and David M. Gibson, 

 Biochim. et Biophys. Acta 29 225 (1958); Salih J. Wakil, J. Am. 

 Chem. Soc. 80 6465 (1958); David M. Gibson, Edward B. Titchener 

 and Salih J. Wakil, Biochim. et Biophys. Acta 30 376 (1958). 



-"Mireille Gastambide-Odier, E. Lederer, Nature 184 1563 (1959). 



