science

NADH:ubiquinone reductase (non-electrogenic)

NADH:ubiquinone reductase (non-electrogenic) is a science 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 NADH:ubiquinone reductase (non-electrogenic) rather than just read about it. In short: NADH:ubiquinone reductase (non-electrogenic) (EC 1.6.5.9, NDH-2, ubiquinone reductase, coenzyme Q reductase, dihydronicotinamide adenine dinucleotide-coenzyme Q reductase, DPNH-coenzyme Q reductase, DPNH-ubiquinone reductase, NADH-coenzyme Q oxidoreductase, NADH-coenzyme Q reductase, NADH-CoQ oxidoreductase, NADH-CoQ reductase) is an enzyme with systematic name NADH:ubiquinone oxidoreductase. This enzyme catalyses t…

Key takeaways

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

Reference excerpt

NADH:ubiquinone reductase (non-electrogenic) (EC 1.6.5.9, NDH-2, ubiquinone reductase, coenzyme Q reductase, dihydronicotinamide adenine dinucleotide-coenzyme Q reductase, DPNH-coenzyme Q reductase, DPNH-ubiquinone reductase, NADH-coenzyme Q oxidoreductase, NADH-coenzyme Q reductase, NADH-CoQ oxidoreductase, NADH-CoQ reductase) is an enzyme with systematic name NADH:ubiquinone oxidoreductase. This enzyme catalyses the following chemical reaction:

NADH + H+ + a quinone ⇌ {\displaystyle \rightleftharpoons } NAD+ + a quinol The 3 substrates of this enzyme are NADH, H+, and a quinone (electron acceptor), whereas its two products are NAD+ and a quinol (reduced acceptor). This enzyme is found in aerobic bacteria and the mitochondria of yeast and plants. In many other organisms (notably the mitochondria of animals), there is a similar enzyme called respiratory complex I, which differs from this enzyme in that it also pumps protons. An important example of this reaction is:

NADH + H+ + ubiquinone ⇌ {\displaystyle \rightleftharpoons } NAD+ + ubiquinol This enzyme is a flavoprotein (FAD). It belongs to the family of oxidoreductases, specifically those acting on NADH or NADPH with other acceptors. The systematic name of this enzyme class is NADH:(quinone-acceptor) oxidoreductase. Other names in common use include reduced nicotinamide adenine dinucleotide (quinone) dehydrogenase, NADH-quinone oxidoreductase, NADH ubiquinone oxidoreductase, DPNH-menadione reductase, D-diaphorase, and NADH2 dehydrogenase (quinone), and mitochondrial (mt) complex I. This enzyme participates in oxidative phosphorylation. Several compounds are known to inhibit this enzyme, including AMP, and 2,4-dinitrophenol. NADH dehydrogenase is involved in the first step of the electron transport chain of oxidative phosphorylation (OXPHOS). Any change in the electron transport component caused by a mutation might effect the normal electron flow. This might be leading "an increase of bifurcation and generation of superoxidase radicals and increase oxidative stress in various types of cancer cells."

Structural studies Several structures are available of this enzyme, which is part of the respiratory chain. It is a multi-subunit enzyme in which this activity is located in the hydrophilic domain. The subunits of the membrane-embedded domain are responsible for proton translocation.

References

Further reading Koli AK, Yearby C, Scott W, Donaldson KO (1969). "Purification and properties of three separate menadione reductases from hog liver". J. Biol. Chem. 244 (4): 621–9. doi:10.1016/S0021-9258(18)94400-5. PMID 4388793.

External links NADH:ubiquinone+reductase+(non-electrogenic) at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

Illustrations

Worked examples

Example 1 — a first encounter with NADH:ubiquinone reductase (non-electrogenic)

Start with the simplest possible case. Write down what NADH:ubiquinone reductase (non-electrogenic) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 NADH:ubiquinone reductase (non-electrogenic) 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 NADH:ubiquinone reductase (non-electrogenic) 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 NADH:ubiquinone reductase (non-electrogenic)

In research: NADH:ubiquinone reductase (non-electrogenic) appears in science 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 NADH:ubiquinone reductase (non-electrogenic) 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: NADH:ubiquinone reductase (non-electrogenic) is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 1.6.5, so understanding it makes those chapters shorter.
In everyday life: Look for NADH:ubiquinone reductase (non-electrogenic) 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 NADH:ubiquinone reductase (non-electrogenic) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NADH:ubiquinone reductase (non-electrogenic) 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 NADH:ubiquinone reductase (non-electrogenic) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NADH:ubiquinone reductase (non-electrogenic) in simple terms?

Why does NADH:ubiquinone reductase (non-electrogenic) matter?

Because it connects several science 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 NADH:ubiquinone reductase (non-electrogenic)?

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 NADH:ubiquinone reductase (non-electrogenic).