TCEP

TCEP (tris(2-carboxyethyl)phosphine) is a strong reducing agent. Compared to dithiothreitol (DTT) and β-mercaptoethanol, TCEP has the advantages of being odorless, a more powerful reducing agent, an irreversible reducing agent, more hydrophilic, and more resistant to oxidation in air. It is soluble in water and stable at neutral pH. It does not reduce metals used in immobilized metal affinity chromatography such as Ni-NTA resin. TCEP is particularly useful when labeling cysteine residues with maleimides.



Note: Make 40 mL 1 M TCEP stock solution

1. Weigh 11.47 g TCEP powder. Dissolve in 20 ml distilled water in a beaker by stirring (may not fully dissolved, but it is OK to proceed to step 2). The resulting solution is at ~ pH 2.5. Wear personal protection.

2. Bring the TCEP solution to pH 7.0 with cold 10 N NaOH prepared in distilled water. Add NaOH solution slowly with stirring, and monitor pH using a pH meter. This step may take an hour or longer to avoid heating up the solution due to heat released from the acid/base reaction. We prepare 10 N NaOH and store at 4 °C.

3. Bring to a final volume of 40 ml with distilled water.

4. Use a vacuum filtering system with 0.22 micron membrane to remove any insoluble species, aliquot and store at -20°C for long-term storage up to two years.