Affinity label
（重定向自Affinity labels）
Affinity labels are molecules similar in structure to a particular substrate for a specific enzyme and are considered to be a class of enzyme inhibitors. These molecules covalently modify active site residues in order to reveal the active site and thus elucidate its structure. The label binds covalently to the enzyme so that the substrate can no longer bind, causing a permanent and irreversible change.