Open AccessPyruvate formate‐lyase is not essential for nitrate respiration by Escherichia coli
Author(s) -
Kaiser M.,
Sawers G.
Publication year - 1994
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1994.tb06759.x
Subject(s) - pyruvate dehydrogenase complex , biochemistry , formate , mutant , escherichia coli , auxotrophy , dehydrogenase , biology , nitrate , respiration , enzyme , chemistry , catalysis , ecology , botany , gene
Defined deletion mutants of Escherichia coli defective for the synthesis of pyruvate formate‐lyase (PFL) or pyruvate dehydrogenase (PDH) were analysed in regards their growth in batch culture and their enzyme levels under fermentative and nitrate respiratory conditions. A pfl mutant proved not to be completely auxotrophic for acetate when grown anaerobically in glucose minimal medium. In contrast, a pfl aceEF double mutant exhibited an absolute requirement for acetate, indicating that PDH is the source of acetyl‐CoA in the pfl mutant. Growth of both pfl and aceEF single mutants under nitrate respiratory conditions was essentially indistinguishable from the wild‐type. Thus, either PFL or PDH can be used to catabolise pyruvate in nitrate‐respiring cells. The activities of PFL and PDH measured after growth with nitrate are commensurate with this proposal.