Application of the two-phase partition assay for chloramphenicol acetyl transferase (CAT) to transfections with simian virus 40-CAT plasmids.

The two-phase partition assay for chloramphenicol acetyl transferase (CAT) was tested for its applicability in transfection experiments involving CAT-expression plasmids containing simian virus 40 (SV40) transcriptional control elements. The assay was shown to be simple, sensitive, reproducible, and, with the modification described, cost-effective. However, CAT transfection experiments themselves gave highly variable results. Yields of CAT per microgram of protein in pSV2-CAT transfections of CV-1 cells varied by 60%. This variability could not be explained by variation in the quality of DNAs used, differences in growth states of the cells at transfection, the culture medium employed, or the time at which transfected cells were extracted for CAT assay.