THE ACETIC ACID BACTERIA 



curred, as in glycerol or sorbitol, this could be reduced to 

 one atom of oxygen per molecule of substrate by including 

 dinitrophenol in the medium. The further oxidation of 

 the one-step oxidation products (dihydroxyacetone or sor- 

 bose) was virtually completely repressed in dinitrophenol 

 solutions, which presumably prevented coenzyme-linked 

 phosphorylations. 



The cells were therefore broken, and cell-free prepara- 

 tions were made. This was accomplished either by dis- 

 integrating the cells in a 10-kc. Raytheon sonic oscillator 

 or by grinding with alumina. The broken cell suspension 

 was mixed with phosphate buffer and centrifuged at 20,000g 

 for an hour; then the residue was re-extracted and the com- 

 bined extracts pooled. 



Particulate Enzymes 



These extracts revealed that the oxidizing enzymes of 

 A. suboxydans varied considerably, more than had been 

 suspected. Two, and sometimes three, systems existed side 

 by side in the organism for the breakdown of individual 

 polyhydroxy compounds. There were, for example, a num- 

 ber of particle-bound, phosphate-independent dehydro- 

 genases (10) which oxidized mannitol, sorbitol, erythritol, 

 glycerol, and glucose to the extent of one atom of oxygen 

 per molecule of substrate. Two atoms of oxygen were 

 used per molecule of ethanol or propanol. The dehydro- 

 genases appeared different from each other, since purifica- 

 tion of the particulate suspensions effected a ten-fold in- 

 crease in the concentration of glucose dehydrogenase (oxi- 

 dase), four-fold for erythritol, three-fold for glycerol, but 

 did not affect the concentration of ethanol dehydrogenase. 



8-D-Gluconolactone has been indicated as the product of 



