Can carbenicillin be substituted for ampicillin when selecting for the pGEM® Vectors?

Yes, the antibiotic carbenicillin can be substituted for ampicillin in antibiotic selection plates when E. coli cells such as JM109 cells (Cat.# L2001) are transformed with or carry any of our pGEM® Vectors. The β-lactamase (bla) gene, which confers resistance to ampicillin, also confers resistance to carbenicillin, a semi-synthetic ampicillin analog. In some cases, carbenicillin may be preferred, as it tends to be more stable than ampicillin (i.e., less likely to break down in the presence of β-lactamases) and can reduce the growth of satellite colonies on plates during long-term incubations (1). Dissolve carbenicillin in a 50% ethanol solution and use at a final concentration of 100µg/ml in solid media.