Analysis of molecules

摘要

There is disclosed a method of analysing one or more molecules having a primary amine or a lysine functionality in two or more samples comprising the steps of: providing a series of reagents having the formula R₁-NH-C(-NH)-OR₂ where R₁ and R₂ are residue groups or atoms, and wherein the chemical formulae of the reagents in the series are identical but each reagent in the series comprises a different combination of isotopes so that reagents in the series are isotopically labelled by way of the molecular mass of each reagent in the series being different to the molecular masses of the other reagents in the series; introducing a different reagent from the series to each sample so as to effect, in each sample, a guanidination reaction between a reagent and moieties having a primary amine or a lysine functionality, thereby producing a plurality of isotopically labelled guanidine or homoarginine derivatives; combining the samples; optionally modifying the isotopically labelled guanidine or homoarginine derivatives to produce further isotopically labelled guanidine or homoarginine derivatives; separating chemically different components of the combined samples whilst substantially retaining together subsets of guanidine or homoarginine derivatives which differ only by virtue of their isotopic labelling; and performing an analysis of one or more subsets of guanidine or homoarginine derivatives which differ only by virtue of their isotopic labelling; in which subsequent to the step of combining the samples the isotopically labelled guanidine or homoarginine derivatives are not selectively bound to a capture reagent.