Expression-activity profiles of cells transfected with prostaglandin endoperoxide H synthase measured by quantitative fluorescence microscopy.

Transfection of cos-1 cells with either prostaglandin endoperoxide H synthase-1 (PGHS-1) or -2 (PGHS-2) results in a mixed population of cells containing a diverse range of expressed enzyme. The use of fluorescent substrates and antibodies, in conjunction with fluorescence microscopy, provides the means to quantitate expression and activity of the enzyme within individual cells. Data obtained from individual cells can be utilized to construct enzyme activity curves for a population of transfected cells. This method has been employed to prepare expression-activity profiles within a population of cos-1 cells expressing PGHS-1 or -2. A direct correlation was observed between enzyme expression and activity as measured in single cells. The data demonstrate that activity-expression analyses can now be performed within single adherent cells growing in tissue culture.