Figure 1.

Protein modification by TG. (A) Protein‐protein crosslinking by TG. TG catalyzes the formation of a covalent bond between glutamine and lysine residues, resulting in crosslinking between two proteins. (B) Structure of biotin‐cadaverine, a cell‐permeating pseudosubstrate for TG. (C) TG‐mediated conjugation between a protein and biotin‐cadaverine. The biotin moiety of biotin‐cadaverine is shown as ‘Bio’. TG catalyzes the conjugation between a glutamine residue in a protein and the amine group of biotin‐cadaverine, yielding protein biotinylation.