Selective release of the periplasmic enzyme beta-lactamase from Escherichia coli with tetradecyl betainate.

The periplasmic enzyme beta-lactamase was selectively released from Escherichia coli K12 by the amphiphilic quaternary ammonium compound tetradecyl betainate at certain concentration intervals. At low concentrations little enzyme was released, and at high concentrations enzyme inactivation occurred. Greater effects of tetradecyl betainate were seen both with respect to release and inactivation at higher pH. At intermediate concentrations of tetradecyl betainate high yields of beta-lactamase were obtained with no detectable contribution of the cytoplasmic marker beta-galactosidase. The highest yields of beta-lactamase activity were obtained when high concentrations of salt were added 1 min after permeation of the bacteria with tetradecyl betainate.