chemistry

TCEP

TCEP is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand TCEP rather than just read about it. In short: TCEP (tris(2-carboxyethyl)phosphine) is a reducing agent frequently used in biochemistry and molecular biology applications. It is often prepared and used as a hydrochloride salt (TCEP-HCl) with a molecular weight of 286.65 gram/mol.

Key takeaways

TCEP belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect TCEP to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of TCEP from memory before moving on to harder problems.

Reference excerpt

TCEP (tris(2-carboxyethyl)phosphine) is a reducing agent frequently used in biochemistry and molecular biology applications. It is often prepared and used as a hydrochloride salt (TCEP-HCl) with a molecular weight of 286.65 gram/mol. It is soluble in water and available as a stabilized solution at neutral pH and immobilized onto an agarose support to facilitate removal of the reducing agent.

Synthesis TCEP can be prepared by the acid hydrolysis of tris(cyanoethyl)phosphine.

Applications TCEP is often used as a reducing agent to break disulfide bonds within and between proteins as a preparatory step for gel electrophoresis. Compared to the other two most common agents used for this purpose (dithiothreitol and β-mercaptoethanol), TCEP has the advantages of being odorless, a more powerful reducing agent, an irreversible reducing agent (in the sense that TCEP does not regenerate—the end product of TCEP-mediated disulfide cleavage is in fact two free thiols/cysteines), more hydrophilic, and more resistant to oxidation in air. It also does not reduce metals used in immobilized metal affinity chromatography. TCEP is particularly useful when labeling cysteine residues with maleimides. TCEP can keep the cysteines from forming di-sulfide bonds and, unlike dithiothreitol and β-mercaptoethanol, it will not react as readily with the maleimide. However, TCEP has been reported to react with maleimide under certain conditions. TCEP is also used in the tissue homogenization process for RNA isolation. For Ultraviolet–visible spectroscopy applications, TCEP is useful when it is important to avoid interfering absorbance from 250 to 285 nanometers which can occur with dithiothreitol. Dithiothreitol will slowly over time absorb more and more light in this spectrum as various redox reactions occur.

History Reduction of biomolecules with trialkyphosphines received little attention for decades because historically available phosphines were extremely malodorous and/or insoluble in water. In 1969, TCEP was reported as an odorless and water-soluble trialkyphosphine suitable for biochemical use, however the potential use of TCEP for biochemical applications was almost totally ignored for decades. In 1991, Burns reported a new convenient synthetic procedure for TCEP, which set off TCEP becoming more widely available and marketed as a "new" reducing agent for biochemical use, & thus TCEP came into more widespread use throughout the 1990s.

Reactions TCEP will reduce disulfides to thiols in the presence of water:

Via a similar process it can also reduce sulfoxides and N-oxides. Some other side reactions have also been reported:

Conversion of a cysteine residue into alanine in the presence of TCEP and heat (90˚C). Slow (but significant, 40% cleavage reported for two week storage at 4˚C) protein backbone cleavage at cysteine residues under mild conditions.

Use in biological research TCEP is available from various chemical suppliers as the hydrochloride salt. When dissolved in water, TCEP-HCl is acidic. A reported preparation is a 0.5 M TCEP-HCl aqueous stock solution that is pH adjusted to near-neutral pH and stored frozen at -20˚C. TCEP is reportedly less stable in phosphate buffers.

See also 2-Mercaptoethanol (BME) Dithiothreitol (DTT) Dithiobutylamine (DTBA)

References

Illustrations

Worked examples

Example 1 — a first encounter with TCEP

Start with the simplest possible case. Write down what TCEP claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to TCEP before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about TCEP ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of TCEP

In research: TCEP appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses TCEP in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: TCEP is common in secondary-school and first-year university syllabi. It links to neighbouring topics Carboxylic acids, Reducing agents, Tertiary phosphines, so understanding it makes those chapters shorter.
In everyday life: Look for TCEP outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “TCEP” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study TCEP in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what TCEP means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain TCEP out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is TCEP in simple terms?

Why does TCEP matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study TCEP?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on TCEP.