INTRODUCTION tris (2-Carboxyethyl) phosphine (TCEP), commercially available as a hydrochloride complex, is an efficient reducing agent most commonly used to reduce disulfide bonds. It is a good substitute for dithiothreitol (DTT) to prevent the formation of intramolecular disulfide bridges in protein, thus preserving their bioactive secondary structure.[1–3] Other uses of TCEP seem to be limited to an analytical tool used for the ...