Carbenicillin

Plasmid stabilization

 * Carbenicillin is used to select for cells bearing the beta-lactamase gene bla or ampR. Beta-lactamase also neutralizes ampicillin, but due to ampicillin's lower effectiveness, carbenicillin tends to give fewer satellite colonies and makes for more reliable cloning. Ampicillin is more widely used, though, due to carbenicillin's high cost ($75/g compared to ampicillin's $10/g (Sigma)).