Fluorigenic enzyme assays using long-wavelength substrates

Investigations into the use of long-wavelength fluorigenic substrates, which are non- or weakly fluorescent but are converted by an appropriate enzyme to a highly fluorescent product, have been carried out in order to determine several different enzymes and their inhibitors. Certain nonfluorescent compounds based on long-wavelength xanthenes and oxazines dyes were synthesised. Amongst these, naphthofluorescein diphosphate and naphthofluorescein mono-phosphate has been demonstrated to be new fluorigenic substrates for alkaline phosphatase. The hydrolysis product of these substrates can be used for trace analyses using diode laser based fluorescence detection. [Continues.]