biology

Lysyl hydroxylase

Lysyl hydroxylase is a biology 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 Lysyl hydroxylase rather than just read about it. In short: Lysyl hydroxylases (or procollagen-lysine 5-dioxygenases) are alpha-ketoglutarate-dependent hydroxylases enzymes that catalyze the hydroxylation of lysine to hydroxylysine. Lysyl hydroxylases require iron and vitamin C as cofactors for their oxidation activity.

Key takeaways

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

Reference excerpt

Lysyl hydroxylases (or procollagen-lysine 5-dioxygenases) are alpha-ketoglutarate-dependent hydroxylases enzymes that catalyze the hydroxylation of lysine to hydroxylysine. Lysyl hydroxylases require iron and vitamin C as cofactors for their oxidation activity. It takes place (as a post-translational modification) following collagen synthesis in the cisternae (lumen) of the rough endoplasmic reticulum (ER). There are three lysyl hydroxylases (LH1-3) encoded in the human genome, namely: PLOD1, PLOD2 and PLOD3. From PLOD2 two splice variant can be expressed (LH2a and LH2b), where LH2b differs from LH2a by incorporating the small exon 13A. LH1 and LH3 hydroxylate lysyl residues in the collagen triple helix, whereas LH2b hydroxylates lysyl residues in the telopeptides of collagen. In addition to its hydroxylation activity, LH3 has glucosylation activity that produces disaccharide (Glc-Gal) attached to collagen hydroxylysines. Collagen lysyl hydroxylation is the first step in collagen pyridinoline cross-linking, that is necessary for the stabilization of collagen.

Reaction catalysed The enzyme converts lysine in proteins into hydroxylysine:

The reaction is important as a first step in cross-lnking collagen. The enzyme is a non-heme iron protein with ferryl active site where Fe(IV)=O is the species that transfers its oxygen to the substrate. The mechanism used by these 2-oxoglutarate-dependent oxygenases requires 2-oxoglutaric acid to activate the iron oxygen complex, and this gives succinic acid and carbon dioxide when the second atom of the molecular oxygen is removed.

Pathology Mutations in the PLOD1 gene have been linked to kyphoscoliotic Ehlers–Danlos syndrome (kEDS, in the past EDS VI).Mutations in the PLOD2 gene have been linked to Bruck syndrome in humans. A deficiency in its cofactor vitamin C is associated with scurvy.

References

External links Lysyl+Hydroxylase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

Illustrations

Worked examples

Example 1 — a first encounter with Lysyl hydroxylase

Start with the simplest possible case. Write down what Lysyl hydroxylase claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, 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 Lysyl hydroxylase 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 Lysyl hydroxylase 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 Lysyl hydroxylase

In research: Lysyl hydroxylase appears in biology 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 Lysyl hydroxylase 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: Lysyl hydroxylase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 1.14.11, Extracellular matrix remodeling enzymes, Genes on human chromosome 1, so understanding it makes those chapters shorter.
In everyday life: Look for Lysyl hydroxylase 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 Lysyl hydroxylase in 20 minutes

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

Frequently asked questions

What is Lysyl hydroxylase in simple terms?

Why does Lysyl hydroxylase matter?

Because it connects several biology 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 Lysyl hydroxylase?

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 Lysyl hydroxylase.