I? 



Alcohols, Glycols and Compounds Related to Sugars 



Thus, the production of acetaldehyde (and subsequently al- 

 cohol) by yeast, the production of acetoin by certain bacteria, 

 etc. 



Although the lipoic acid mechanism was first demonstrated 

 in Streptococcus faecalis, all bacteria do not require the cofac- 

 tor for this transformation. 



The role of acetylcoenzyme A in cellular synthesis of fatty 

 acids will be seen later. Butanol is probably formed by reduc- 

 tion of acetoacetylcoenzyme A. It is interesting to note that 

 some microorganisms can synthesize a variety of carbohydrates 

 by using acetate as the sole carbon source, in effect reversing 

 the process (e.g.^). Pyruvate is also converted to succinate by 

 fixation of COo. 



Various other fates of pyruvate are known. For example, 

 there are bacteria which dismutate 2 moles of pyruvate to 

 1 mole each of acetic and lactic acids. *^ Also Bacillus coli is 

 known to convert pyruvate to a mixture of acetic and formic 

 acids. ^ 



The pentose phosphate cycle mentioned earlier probably oc- 

 curs in many microorganisms. It is outlined below: 



Ribulose-5-P < » Ribose-5-P 



TPNH 



+H© 



TPN© 



CO2 



6-Phosphogluconic 



Acid \ >r TPNH 



+ H© 



Xylulose-5-P 



Glucose 



ATP 



Dihydroxy- 

 Qcetone-P 



Glyceralde 

 hyde-3-P 



♦ Fructose-6-P 



Glyceralde- 

 hyde-3-P 



Sedoheptu- 

 ose-7-P 



Erythrose-4-P 



Xylulose-5-P 



Enzyme-catalyzed reactions of the pentose 

 phosphate pathway* 



* This diagram together with the summarizing equations is re- 

 printed with permission from Joseph S. Fruton and Sofia Simmonds, 

 "General Biochemistry," John Wiley and Sons, Inc., New York, N. Y., 

 1958, p. 531. 



5 V. I. Lyubimov, Doklady Akad. Nauk SSSR III No. 4 (1956). 



" Seymour Karkes, Alice del Campillo, I. C. Gunsalus and Severe 

 Ochoa, J. Biol. Chem. 193 721 (1952). 



^ Kenneth V. Thimann, "The Life of Bacteria," Macmillan Co., 

 New York, N. Y. 1955, pp. 441-465. 



