Labeling methodology comprising oligopeptides

A method for providing a labeled target protein or labeled target peptide, which method comprises the steps of:

• a. contacting a chemical molecule, which chemical molecule comprises, spacer and/or linker residues, and optionally comprises the following parts
• a target protein or a target peptide residue which is covalently bound as one of both terminal groups of said chemical molecule to a chemical backbone, which chemical backbone consists of amino acids and/or spacers and optionally linkers, covalently bound to each other, and which backbone contains a spacer and/or linker residues, and optionally contains
• one amino acid or spacer residue as the second of both terminal groups of said chemical molecule covalently bound to a reversible or irreversible affinity tagging residue, with the proviso that in case that the affinity tagging residue is an irreversible affinity tagging residue, there is at least one linker residue covalently bound to said amino acid or spacer residue, which amino acid or spacer residue is on the other hand covalently bound to the irreversible affinity tagging residue, and
• one amino acid or spacer residue covalently bound to a labeling residue which labeling residue may be detected by physical means,
• with an affinity support, to obtain said chemical molecule bound to the affinity support via the affinity tag of the affinity tagging residue,
• b. removing impurities in the reaction mixture surrounding the affinity support to which the chemical molecule according to step a. is bound, and
• c. cleaving or eluting said chemical molecule from said affinity support to obtain
• (i) in case of an irreversible affinity tagging residue, a labeled target protein or labeled peptide comprising a chemical backbone, which backbone contains a spacer and/or linker residues, and optionally contains one amino acid or spacer residue covalently bound to a labeling residue which labeling residue may be detected by physical means,
• (ii) in case of a reversible affinity tagging residue, a chemical backbone covalently bound to a protein or a peptide residue, which backbone contains a spacer and/or linker residues, and optionally contains
• one amino acid or spacer residue covalently bound to a labeling residue which labeling residue may be detected by physical means,
• one amino acid or spacer residue covalently bound to a labeling residue, which labeling residue may be detected by physical means, and which labeling residue or spacer residue is covalently bound to a reversible affinity tagging residue.