Quantitative aspects of the use of bacterial chloramphenicol acetyltransferase as a reporter system in the yeast Saccharomyces cerevisiae.

The quantitative aspects of the use of the reporter system chloramphenicol acetyltransferase (CAT) has been evaluated in the yeast Saccharomyces cerevisiae. It was found that the CAT activity measured with a radiosotopic fluor diffusion assay was strongly dependent on the amount of yeast extract applied, both when CAT was expressed endogenously and when a purified Escherichia coli enzyme was investigated. Desalting the yeast extract by gel filtration partly eliminated the problem, indicating that some low-molecular-weight compound was involved in the phenomenon. However, the extract still exhibited stability problems on ice. An immunological CAT assay was tested and found to yield satisfactory quantitative result.