Catalytically generated mass labels

Abstract

Provided is a method for assaying a substance, which method comprises contacting the substance with an assay agent comprising a catalytic agent to associate the substance with the catalytic agent, contacting the resulting associated substance with a label precursor, and detecting a label, wherein the label precursor is capable of reacting catalytically with the catalytic agent to release the label, and wherein the label is a mass label. Also provided is 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.

1 . A method for assaying a substance, which method comprises contacting the substance with an assay agent comprising a catalytic agent to associate the substance with the catalytic agent, contacting the resulting associated substance with a label precursor, and detecting a label, wherein the label precursor is capable of reacting catalytically with the catalytic agent to release the label, and wherein the label is a mass label.  
     
     
         2 . A method according to  claim 1 , wherein the catalytic agent is capable of cleaving a specific chemical bond, or a bond in a specific molecular environment.  
     
     
         3 . A method according to  claim 1  or  claim 2 , wherein prior to contacting the associated substance with the label precursor, the associated substance is separated from unassociated assay agent.  
     
     
         4 . 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.  
     
     
         5 . A method according to  claim 4 , wherein the carrier moiety is selected such that it allows the label precursor to be captured on a solid phase.  
     
     
         6 . A method according to  claim 5 , wherein the carrier moiety comprises biotin for attaching the label precursor to an avidinated solid phase.  
     
     
         7 . A method according to any preceding claim, wherein the assay agent comprises a recognition moiety which is capable of associating with a specific substance.  
     
     
         8 . A method according to  claim 7 , wherein the recognition moiety comprises an antibody, an oligonucleotide, a protein, a peptide, an enzyme, an RNA aptamer and/or a dextran.  
     
     
         9 . A method according to any preceding claim, wherein the catalytic agent comprises an organic catalyst, a protein enzyme and/or a catalytic RNA molecule.  
     
     
         10 . A method according to  claim 9 , wherein the catalytic agent comprises a hydrolytic enzyme, such as lysozyme, trypsin, chymotrypsin, an elastase, an alkaline phosphitase or a peroxidase.  
     
     
         11 . 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.  
     
     
         12 . 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.  
     
     
         13 . A method according to  claim 12 , wherein each label precursor comprises a label attached to a carrier moiety via a linker and the carrier moiety of each label precursor is selected such that it has a different mass to each of the mass labels in the array of label precursors.  
     
     
         14 . A method for gene profiling comprising detecting one or more mRNA moieties by means of a method as defined in any preceding claim.  
     
     
         15 . 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.  
     
     
         16 . A kit according to  claim 15  for assaying a mixture of substances, which kit comprises an assay agent comprising an array of catalytic agents and an array of label precursors, 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.  
     
     
         17 . A kit according to  claim 15  or  claim 16 , wherein the catalytic agent is capable of cleaving a specific chemical bond, or a bond in a specific molecular environment.  
     
     
         18 . A kit according to any of claims  15 - 17 , 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.  
     
     
         19 . A kit according to any of claims  18 , wherein the carrier moiety is selected such that it allows the label precursor to be captured on a solid phase.  
     
     
         20 . A kit according to  claim 19 , wherein the carrier moiety comprises biotin for attaching the label precursor to an avidinated solid phase.  
     
     
         21 . A kit according to any of claims  15 - 20 , wherein the assay agent comprises a recognition moiety which is capable of associating with a specific substance.  
     
     
         22 . A kit according to any of claims  15 - 21 , wherein the assay agent comprises an antibody, an oligonucleotide, a protein, a peptide, an enzyme, an RNA aptamer and/or a dextran.  
     
     
         23 . A kit according to any of claims  15 - 22 , wherein the catalytic agent comprises an organic catalyst, a protein enzyme and/or a catalytic RNA molecule.  
     
     
         24 . A kit according to  claim 23 , wherein the catalytic agent comprises a hydrolytic enzyme, such as lysozyme, trypsin, chymotrypsin, an elastase, an alkaline phosphitase or a peroxidase.  
     
     
         25 . A kit according to any of claims  15 - 24 , 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.  
     
     
         26 . A kit according to any of claims  16 - 25 , wherein each label precursor comprises a label attached to a carrier moiety via a linker and the carrier moiety of each label precursor is selected such that it has a different mass to each of the mass labels in the array of label precursors.