18 METABOLIC PATHWAYS IN MICROORGANISMS 



is unusual, although a related directing of metabolism 

 toward glycolysis (DPN) or the pentose cycle (TPN) has been 

 noted in animal systems in our laboratory (32), as well as 

 by Wenner and Weinhouse (33). 



Pyruvate, Pyruvate conversion to acetate in A. suboxy- 

 dans follows an interesting course (34, 35). Whereas in 

 animals and most other aerobic organisms, the highlight 

 of pyruvate oxidation is terminal consumption through the 

 Krebs cycle, in this organism there is ample opportunity 

 to recognize breakdown products from pyruvate that have 

 more than a transient existence. The details of formation 

 of some of the minor products also differ. Although in 

 animals and most bacteria, pyruvate is converted in small 



TABLE 1.7 



Comparison of Substrate Specificity of A, suhoxydans 

 and Yeast Pyruvic Carboxylase 



Yeast * 



* Recalculated from the data of Green et al. (36) and Kobayasi 



A direct quantitative comparison is not possible because of differ- 

 ences in test conditions. The numbers represent relative rates of 

 decarboxylation compared to the rate with pyruvic acid. [After King 

 and Cheldelin (34).] 



