Homo-doubly labeled compositions for the detection of enzyme activity in biological samples

A mammalian cell comprising a fluorogenic composition comprising a polypeptide backbone or a nucleic acid backbone joining two identical fluorophores whereby said fluorophores form an H-dimer resulting in the quenching of the fluorescence of said fluorophores.

A method of detecting the activity of a protease, said method comprising:

• i) contacting said protease with a fluorogenic composition comprising a polypeptide backbone joining two fluorophores of the same species whereby said fluorophores form an H-dimer resulting in quenching of the fluorescence of said fluorophores;
• and
• ii) detecting a change in fluorescence or absorbance of said fluorogenic composition where an increase in fluorescence or a change in absorbance indicates that said protease cleaves said polypeptide backbone.

A method of detecting the activity of a nuclease or the presence of a nucleic acid, said method comprising:

• i) contacting said nuclease or said nucleic acid with a fluorogenic composition comprising a nucleic acid backbone joining two fluorophores of the same species whereby said fluorophores form an H-dimer resulting in quenching of the fluorescence of said fluorophores;
• and
• ii) detecting a change in fluorescence or absorbance of said fluorogenic composition where an increase in fluorescence or a change in absorbance indicates that said nuclease cleaves said nucleic acid backbone or that said nucleic acid hybridizes to said backbone.

A method of detecting a change in conformation or cleavage of a macromolecule, said method comprising:

• i) providing a macromolecule having attached thereto two fluorophores of the same species whereby said fluorophores form an H-dimer resulting in quenching of the fluorescence of said fluorophores;
• and
• ii) detecting a change in fluorescence or absorbance of said fluorophores wherein a change in fluorescence or absorbance indicates a change in conformation or cleavage of said macromolecule.