ANAEROBIC INDUCTION OF SUPEROXIDE DISMUTASE IN ESCHERICHIA COLI BY NITRATE RESPIRATION

Abstract

Previously, we demonstrated that nitrate respiration increases the synthesis of iron-containing superoxide dismutase (Fe SOD) in anaerobically grown Escherichia coli cells. In this study, we developed a system with which the anaerobic induction of Fe SOD by nitrate respiration in E. coli was separated from the induction of the nitrate respiration system. The anaerobic induction of Fe SOD required the presence of both nitrate and an electron donor, and the induction of Fe SOD by nitrate respiration was inhibited by chloramphenicol or riphampicin. When glucose was used as the electron donor, carbonyl cyanide p-trifluoro-methoxyphenyl-hydrazone (FCCP) but not N, N′-dicyclohexylcarbodiimide (DCCD) inhibited the induction of Fe SOD by nitrate respiration, but when formate was used as the donor, both FCCP and DCCD inhibited the induction of Fe SOD by nitrate respiration.