Catalytically generated mass labels

A method according to any preceding claim, in which the label precursor comprises a label attached to a carrier moiety via a linker, the label being specific to the linker, and wherein the linker is capable of being cleaved by a specific catalytic agent to release the label.

A method according to any preceding claim, wherein the assay agent comprises a recognition moiety which is capable of associating with a specific substance.

A method according to any preceding claim, wherein the catalytic agent comprises an organic catalyst, a protein enzyme and/or a catalytic RNA molecule.

A method according to any preceding claim, wherein the catalytic agent comprises an endonuclease and the label precursor comprises an oligonucleotide linker capable of being cleaved catalytically by the endonuclease to release the label.

A method according to any preceding claim for assaying a mixture comprising a plurality of substances, which method comprises contacting the mixture with an assay agent comprising an array of catalytic agents to associate each substance in the mixture with a catalytic agent specific to that substance, contacting the resulting associated substances with an array of label precursors, and detecting a plurality of labels, wherein each catalytic agent in the array is specific to one substance in the mixture, each label precursor is capable of reacting catalytically with a catalytic agent specific to that precursor to release a label, and each label is specific to its precursor and is a mass label.

A method for gene profiling comprising detecting one or more mRNA moieties by means of a method as defined in any preceding claim.

A kit for assaying a substance, which kit comprises an assay agent comprising a catalytic agent, and a label precursor capable of reacting catalytically with the catalytic agent to release a label, wherein the label is a mass label.