Positively coded photoaffinity label for altering isoelectric points of proteins

Novel diazirinyl photoaffinity ligand, which contains (3-trifluoromethyl) phenyldiazirine and penta(ε-Boc-Lys) as a photoreactive code, allows the introduction of a positive cascade to alter the pI value of labeled components, facilitating the isolation of photolabeled biocomponents with isoelectric focusing techniques.