chemistry

Trimethylamine N-oxide

Trimethylamine N-oxide 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 Trimethylamine N-oxide rather than just read about it. In short: Trimethylamine N-oxide (TMAO) is an organic compound with the formula (CH3)3NO. It is in the class of amine oxides.

Key takeaways

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

Reference excerpt

Trimethylamine N-oxide (TMAO) is an organic compound with the formula (CH3)3NO. It is in the class of amine oxides. Although the anhydrous compound is known, trimethylamine N-oxide is usually encountered as the dihydrate. Both the anhydrous and hydrated materials are white, water-soluble solids. TMAO is found in the tissues of marine crustaceans and marine fish, where it prevents water pressure from denaturing proteins and ultimately prevents the death of the animal. The concentration of TMAO increases with the depth at which the animal lives; TMAO is found in high concentrations in the deepest-living described fish species, Pseudoliparis swirei, which was found in the Mariana Trench, at a recorded depth of 8,076 m (26,496 ft). In animals, TMAO is a product of the oxidation of trimethylamine, a common metabolite of trimethyl quaternary ammonium compounds, like choline, trimethylglycine, and L-carnitine. High TMAO concentrations are associated with an increased risk of all-cause mortality and cardiovascular disease.

Marine animals Trimethylamine N-oxide is an osmolyte found in molluscs, crustaceans, and all marine fishes and bony fishes. It is a protein stabilizer that serves to counteract the protein-destabilizing effects of pressure. In general, the bodies of animals living at great depths are adapted to high pressure environments by having pressure-resistant biomolecules and small organic molecules present in their cells, known as piezolytes, of which TMAO is the most abundant. These piezolytes give the proteins the flexibility they need to function properly under great pressure. TMAO decomposes to trimethylamine (TMA), which is the main odorant that is characteristic of degrading seafood.

TMAO in diet TMAO levels increase with consumption of animal protein such as red meat, shellfish, and total fish consumption. Plant-based diets such as vegan, vegetarian and the Mediterranean diet lower TMAO levels.

Chemistry TMAO can be synthesized from trimethylamine by treatment with hydrogen peroxide:

(CH3)3N + H2O2 → H2O + (CH3)3NO The dihydrate is dehydrated by azeotropic distillation from dimethylformamide.

Laboratory applications Trimethylamine oxide is used in protein folding experiments to counteract the unfolding effects of urea. In the organometallic chemistry reaction of nucleophilic abstraction, (CH3)3NO is employed as a decarbonylation agent according to the following stoichiometry:

M(CO)n + (CH3)3NO + L → M(CO)n−1L + (CH3)3N + CO2 where M is a metal. This reaction is used to decomplex organic ligands from metals, e.g. from (diene)Fe(CO)3. It is used in certain oxidation reactions, e.g. the conversion of alkyl iodides to the corresponding aldehyde.

Effects on protein stability The effects of TMAO on the backbone and charged residues of peptides are found to stabilize compact conformations, whereas effects of TMAO on nonpolar residues lead to peptide swelling. This suggests competing mechanisms of TMAO on proteins, which accounts for hydrophobic swelling, backbone collapse, and stabilization of charge-charge interactions. These mechanisms are observed in Trp cage.

Disorders

Trimethylaminuria

Trimethylaminuria is a rare defect in the production of the enzyme flavin-containing monooxygenase 3 (FMO3). Those suffering from trimethylaminuria are unable to convert choline-derived trimethylamine into trimethylamine oxide. Trimethylamine then accumulates and is released in the person's sweat, urine, and breath, giving off a strong fishy odor.

Health effects

Mortality High circulating TMAO concentrations are associated with an increased risk of all-cause mortality.

Cardiovascular disease High circulating TMAO concentrations are associated with an increased risk of cardiovascular events and strokes in particular.

Hypertension High circulating TMAO concentrations are associated with an increased risk of hypertension.

Potential toxicity Exposure limit guidelines with a detailed description of toxicity are available such as "Recommendation from the Scientific Committee on Occupational Exposure Limits" by the European Union Commission.

Illustrations

Worked examples

Example 1 — a first encounter with Trimethylamine N-oxide

Start with the simplest possible case. Write down what Trimethylamine N-oxide 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 Trimethylamine N-oxide 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 Trimethylamine N-oxide 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 Trimethylamine N-oxide

In research: Trimethylamine N-oxide 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 Trimethylamine N-oxide 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: Trimethylamine N-oxide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Amine oxides, Lipid disorders, Methyl compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Trimethylamine N-oxide 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.

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How to study Trimethylamine N-oxide in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Trimethylamine N-oxide 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 Trimethylamine N-oxide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Trimethylamine N-oxide in simple terms?

Trimethylamine N-oxide (TMAO) is an organic compound with the formula (CH3)3NO. It is in the class of amine oxides.

Why does Trimethylamine N-oxide 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 Trimethylamine N-oxide?

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 Trimethylamine N-oxide.