CONTROL OF CELLULAR-ACTIVITY OF DISSIMILATORY NITRATE REDUCTASE IN ESCHERICHIA-COLI

Dissimilatory nitrate reductase (DNR) in Escherichia coli cells grown under anaerobic conditions with KNO3 was activated upon incubation of the cells with NaCl and inactivated with cysteine or glutathione (GSH). Cysteine was shown to exert its effect, at least in part, after conversion to GSH. NaCl-induced activation of DNR was prevented by concomitant addition of the extracts of many kinds of vegetable, although none of the extracts inactivated it when added in the absence of NaCl. Further, the vegetable extracts, in contrast to cysteine or GSH, were found to inhibit DNR activity itself when added to the reaction mixture for the enzyme assay.