Inhibition of Enzyme Induction in E. Coli by Anodic Silver

Abstract

A silver anode, but not a cathode, is bactericidal at microampere current levels because of the electrochemical reactions occurring at the metal electrode surface. This has been clinically useful as a local anti-infective agent even though the mechanism of action on the bacterial cell has not been determined. We investigated the effect by inducing β-galactosidase while passing current though cultures of Escherichia coli. Enzyme induction was depressed in the silver anode chamber within twenty minutes of initiation of current (0.04 to 40 μA); induction in the connected silver cathode chamber was normal. The inhibition at the anode is not the result of electrolysis of the medium nor is the electric current itself required, since pre-anodized silver is inhibitory. The electrochemical products are effective even after derepression has occurred. They appear to act on the process of protein production itself rather than directly on the liberated β-galactoside enzyme.