| abstract |
The present invention relates to a method of detecting a biologically active substance affecting intracellular processes, the method comprising: (a) culturing a cell containing a DNA sequence coding for (i) a green fluorescent protein (GFP) having a protein kinase recognition site, or (ii) a green fluorescent protein wherein one or more amino acids have been substituted, inserted or deleted to provide a binding domain of a second messenger or an enzyme recognition site, or (iii) a hybrid polypeptide of green fluorescent protein (GFP) or a modified GFP and an enzyme recognition site or a binding domain for a second messenger under conditions permitting expression of the DNA sequence; (b) measuring the fluorescence of the cell; (c) incubating the cell with a sample suspected of containing a biologically active substance affecting intracellular processes; and (d) measuring the fluorescence produced by the incubated cell and determining any change in the fluorescence compared to the fluorescence measured in step (b), such change being indicative of the presence of a biologically active substance in said sample. |