Nalidixic acid-induced protein alterations in Escherichia coli.

The effect of nalidixic acid on pulse-labeled protein patterns was analyzed by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. The drug was found to alter protein patterns in a drug-sensitive strain but not in the isogenic drug-resistant strain of Escherichia coli. The drug-induced alteration of protein patterns was demonstrated by the appearance of some and the disappearance of other pulse-labeled peptides elicited by the drug.