An improved fluor diffusion assay for chloramphenicol acetyltransferase gene expression.

We report on a substantial improvement of the widely used fluor diffusion assay for chloramphenicol acetyltransferase (CAT) activity. The stable and inexpensive [3H]NaAcetate along with yeast acetyl CoA synthetase is used to produce [3H]acetyl CoA with high specific radioactivity and high yield. In a second step, the enzymatically produced [3H]acetyl CoA is introduced as a substrate for CAT in the fluor diffusion assay. Due to these modifications, the assay becomes more sensitive, the range of linearity is increased by two orders of magnitude and the assay becomes less costly.