engineering

Homocysteine desulfhydrase

Homocysteine desulfhydrase 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 Homocysteine desulfhydrase rather than just read about it. In short: The enzyme homocysteine desulfhydrase (EC 4.4.1.2) catalyzes the chemical reaction L-homocysteine + H2O = hydrogen sulfide + NH3 + 2-oxobutanoate (overall reaction) (1a) L-homocysteine = hydrogen sulfide + 2-aminobut-2-enoate (1b) 2-aminobut-2-enoate = 2-iminobutanoate (spontaneous) (1c) 2-iminobutanoate + H2O = 2-oxobutanoate + NH3 (spontaneous) This enzyme belongs to the family of lyases, specifically the class of…

Key takeaways

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

Reference excerpt

The enzyme homocysteine desulfhydrase (EC 4.4.1.2) catalyzes the chemical reaction

L-homocysteine + H2O = hydrogen sulfide + NH3 + 2-oxobutanoate (overall reaction) (1a) L-homocysteine = hydrogen sulfide + 2-aminobut-2-enoate (1b) 2-aminobut-2-enoate = 2-iminobutanoate (spontaneous) (1c) 2-iminobutanoate + H2O = 2-oxobutanoate + NH3 (spontaneous) This enzyme belongs to the family of lyases, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is L-homocysteine hydrogen-sulfide-lyase (deaminating; 2-oxobutanoate-forming). Other names in common use include homocysteine desulfurase, L-homocysteine hydrogen-sulfide-lyase (deaminating). This enzyme participates in nitrogen and sulfur metabolism. It employs one cofactor, pyridoxal phosphate.

References

Kallio RE (September 1951). "Function of pyridoxal phosphate in desulfhydrase systems of Proteus morganii". The Journal of Biological Chemistry. 192 (1): 371–7. doi:10.1016/S0021-9258(18)55941-X. PMID 14917685.

Worked examples

Example 1 — a first encounter with Homocysteine desulfhydrase

Start with the simplest possible case. Write down what Homocysteine desulfhydrase 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 Homocysteine desulfhydrase 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 Homocysteine desulfhydrase 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 Homocysteine desulfhydrase

In research: Homocysteine desulfhydrase 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 Homocysteine desulfhydrase 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: Homocysteine desulfhydrase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 4.4.1, Enzyme stubs, Enzymes of unknown structure, so understanding it makes those chapters shorter.
In everyday life: Look for Homocysteine desulfhydrase 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 Homocysteine desulfhydrase in 20 minutes

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

Frequently asked questions

What is Homocysteine desulfhydrase in simple terms?

The enzyme homocysteine desulfhydrase (EC 4.4.1.2) catalyzes the chemical reaction L-homocysteine + H2O = hydrogen sulfide + NH3 + 2-oxobutanoate (overall reaction) (1a) L-homocysteine = hydrogen sulfide + 2-aminobut-2-enoate (1b) 2-aminobut-2-enoate = 2-iminobutanoate (spontaneous) (1c) 2-iminobut…

Why does Homocysteine desulfhydrase 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 Homocysteine desulfhydrase?

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 Homocysteine desulfhydrase.