Probe sets for the multiplexed detection of the binding of, or interaction
between, one or more ligands and target antiligands are provided. Detection involves
the release of identifying tags as a consequence of target recognition. The probe
sets include electrophoretic tag probes or e-tag probes, comprising a detection
region and a mobility-defining region called the mobility modifier, both linked
to a target-binding moiety. The probes comprise interactive functionalities adjacent
the cleaved portion positioned in the probes such that the interactive functionality
does not form part of the e-tag reporters. Target antiligands are contacted with
a set of e-tag probes and the contacted antiligands are treated with a selected
cleaving agent resulting in a mixture of e-tag reporters and uncleaved and/or partially
cleaved e-tag probes. The mixture is exposed to a capture agent effective to bind
to uncleaved or partially cleaved e-tag probes, followed by electrophoretic separation.
In a multiplexed assay, different released e-tag reporters may be separated and
detected providing for target identification.