engineering

Nitrous-oxide reductase

Nitrous-oxide reductase is a engineering 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 Nitrous-oxide reductase rather than just read about it. In short: In enzymology, a nitrous oxide reductase also known as nitrogen:acceptor oxidoreductase (N2O-forming) is an enzyme that catalyzes the final step in bacterial denitrification, the reduction of nitrous oxide to dinitrogen. N2O + 2 reduced cytochome c ⇌ N2 + H2O + 2 cytochrome c It plays a critical role in preventing release of a potent greenhouse gas into the atmosphere.

Key takeaways

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

Reference excerpt

In enzymology, a nitrous oxide reductase also known as nitrogen:acceptor oxidoreductase (N2O-forming) is an enzyme that catalyzes the final step in bacterial denitrification, the reduction of nitrous oxide to dinitrogen.

N2O + 2 reduced cytochome c ⇌ N2 + H2O + 2 cytochrome c It plays a critical role in preventing release of a potent greenhouse gas into the atmosphere.

Function N2O is an inorganic metabolite of the prokaryotic cell during denitrification. Thus, denitrifiers comprise the principal group of N2O producers, with roles played also by nitrifiers, methanotrophic bacteria, and fungi. Among them, only denitrifying prokaryotes have the ability to convert N2O to N2. Conversion of N2O into N2 is the last step of a complete nitrate denitrification process and is an autonomous form of respiration. N2O is generated in the denitrifying cell by the activity of respiratory NO reductase. Some microbial communities only have the capability of N2O reduction to N2 and do not possess the other denitrification pathways. Such communities are known as nitrous oxide reducers. Some denitrifiers do not have complete denitrification with end product N2O

Structure Nitrous-oxide reductase is a homodimer that is located in the bacterial periplasm. X-ray structures of the enzymes from Pseudomonas nautica and Paracoccus denitrificans have revealed that each subunit (MW=65 kDa) is organized into two domains. One cupredoxin-like domain contains a binuclear copper protein known as CuA. The second domain comprises a 7-bladed propeller of β-sheets that contains the catalytic site called CuZ, which is a tetranuclear copper-sulfide cluster. The distance between the CuA and CuZ centers within a single subunit is greater than 30Å, a distance that precludes physiologically relevant rates of intra-subunit electron transfer. However, the two subunits are orientated "head to tail" such that the CuA center in one subunit lies only 10 Å from the CuZ center in the second ensuring that pairs of redox centers in opposite subunits form the catalytically competent unit. The CuA center can undergo a one-electron redox change and hence has a function similar to that in the well-known aa3-type cytochrome c oxidases (EC 1.9.3.1) where it serves to receive an electron from soluble cytochromes c.

Inhibitors Acetylene is the most specific inhibitor of nitrous-oxide reductase. Other inhibitors include azide anion, thiocyanate, carbon monoxide, iodide, and cyanide.

References

Illustrations

Worked examples

Example 1 — a first encounter with Nitrous-oxide reductase

Start with the simplest possible case. Write down what Nitrous-oxide reductase claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, 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 Nitrous-oxide reductase 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 Nitrous-oxide reductase 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 Nitrous-oxide reductase

In research: Nitrous-oxide reductase appears in engineering 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 Nitrous-oxide reductase 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: Nitrous-oxide reductase is common in secondary-school and first-year university syllabi. It links to neighbouring topics Copper enzymes, EC 1.7.2, Enzymes of known structure, so understanding it makes those chapters shorter.
In everyday life: Look for Nitrous-oxide reductase 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 Nitrous-oxide reductase in 20 minutes

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

Frequently asked questions

What is Nitrous-oxide reductase in simple terms?

Why does Nitrous-oxide reductase matter?

Because it connects several engineering 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 Nitrous-oxide reductase?

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 Nitrous-oxide reductase.