Patent ID: 7223610

Claim:
A method for measuring the phosphorylation state of biological molecules in a sample, consisting essentially of tagging said molecules with fluorescent markers and activating said fluorescent markers by irradiating the sample with light, the method further comprising the steps of: (a) selecting a fluorescent marker, whose fluorescence lifetime assumes a different value depending upon the presence or absence of phosphate groups in its vicinity; (b) attaching the fluorescent marker selected in step (a) to a biomolecule; (c) measuring the fluorescence lifetime of the fluorescent marker in a sample containing the biomolecule with the fluorescent marker attached in accordance with step (b); and (d) classifying the biomolecules in the sample in accordance with the presence or absence of phosphate groups attached to said biomolecules, while basing said classifying on the different lifetime of each fluorescence marker.