Leakage of periplasmic enzymes by mutants of Escherichia coli and Salmonella typhimurium: isolation of "periplasmic leaky" mutants.

Mutants of Escherichia coli and Salmonella typhimurium were selected on the basis of their spontaneous leakage of ribonuclease I. The mutants also leaked several other periplasmic enzymes into the medium during active growth but did not leak the intracellular enzymes glucose-6-phosphate dehydrogenase or phosphoglucose isomerase.