Abstract
SUMMARY: A strain of Escherichia coli with a mutation in the ana gene was shown to lack acetaldehyde dehydrogenase and alcohol dehydrogenase. The requirement of this strain for an external oxidant to grow anaerobically on glucose shows that the reduction of acetyl-CoA is the principal means of reoxidation of NADH produced during glycolysis in E. coli. Further mutants derived from the ana strain were shown to be affected in the enzymes involved in the fermentation of pyruvate (pyruvate formate-lyase, phosphotransacetylase, acetate kinase). A gene controlling acetate kinase (ackB) activity has been located at 39 min on the chromosomal map. Evidence is presented that anaerobic nitrite reduction with pyruvate involves at least the dehydrogenase subunit of the pyruvate dehydrogenase complex.