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Prostacyclin synthase

Prostacyclin synthase 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 Prostacyclin synthase rather than just read about it. In short: Prostaglandin-I synthase (EC 5.3.99.4) also known as prostaglandin I2 (prostacyclin) synthase (PTGIS) or CYP8A1 is an enzyme involved in prostanoid biosynthesis that in humans is encoded by the PTGIS gene. This enzyme belongs to the family of cytochrome P450 isomerases.

Prostacyclin synthase — main illustration
Prostacyclin synthase — illustration

Key takeaways

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

Reference excerpt

Prostaglandin-I synthase (EC 5.3.99.4) also known as prostaglandin I2 (prostacyclin) synthase (PTGIS) or CYP8A1 is an enzyme involved in prostanoid biosynthesis that in humans is encoded by the PTGIS gene. This enzyme belongs to the family of cytochrome P450 isomerases.

Function This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. However, this protein is considered a member of the cytochrome P450 superfamily on the basis of sequence similarity rather than functional similarity. This endoplasmic reticulum membrane protein catalyzes the conversion of prostaglandin H2 to prostacyclin (prostaglandin I2), a potent vasodilator and inhibitor of platelet aggregation. An imbalance of prostacyclin and its physiological antagonist thromboxane A2 contribute to the development of myocardial infarction, stroke, and atherosclerosis. Unlike most P450 enzymes, PGIS does not require molecular oxygen (O2). Instead it uses its heme cofactor to catalyze the isomerization of prostaglandin H2 to prostacyclin. Prostaglandin H2 is produced by cyclooxygenase in the first committed step of prostaglandin biosynthesis.

Nomenclature The systematic name of this enzyme class is (5Z,13E)-(15S)-9alpha,11alpha-epidioxy-15-hydroxyprosta-5,13-dienoate 6-isomerase. Other names in common use include prostacyclin synthase, prostacyclin synthetase, prostagladin I2 synthetase, PGI2 synthase, PGIS, PTGIS, and PGI2 synthetase.

Pathways

Molecular interactions Generally, protein–protein interactions play crucial roles and are critical for formation of protein microenvironment, cell signaling and direct regulation of the activity of metabolic enzymes. Information on tissue-specific spectrum of molecular interactions of prostacyclin synthase will be useful for subnetwork analysis of PTGIS. Following proteins became known as potential direct binders of PTGIS: CYP2J2, GST, GSTA1, GLRX3, AKR1A1. Protein–protein and protein-peptide interactions were experimentally verified using surface plasmon resonance technology.

See also Prostanoid

References

Further reading

External links prostacyclin+synthetase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) This article incorporates text from the United States National Library of Medicine, which is in the public domain.

Illustrations

Prostacyclin synthase illustration
Prostacyclin synthase illustration
Prostacyclin synthase illustration
Prostacyclin synthase illustration
Prostacyclin synthase: Thromboxane synthesis
Thromboxane synthesis

Worked examples

Example 1 — a first encounter with Prostacyclin synthase

Start with the simplest possible case. Write down what Prostacyclin synthase 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 Prostacyclin synthase 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 Prostacyclin synthase 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 Prostacyclin synthase

In research
Prostacyclin synthase 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 Prostacyclin synthase 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
Prostacyclin synthase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 5.3.99, Enzymes of known structure, Genes on human chromosome 20, so understanding it makes those chapters shorter.
In everyday life
Look for Prostacyclin synthase 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 Prostacyclin synthase in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Prostacyclin synthase means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Prostacyclin synthase out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Prostacyclin synthase in simple terms?

Prostaglandin-I synthase (EC 5.3.99.4) also known as prostaglandin I2 (prostacyclin) synthase (PTGIS) or CYP8A1 is an enzyme involved in prostanoid biosynthesis that in humans is encoded by the PTGIS gene. This enzyme belongs to the family of cytochrome P450 isomerases.

Why does Prostacyclin synthase 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 Prostacyclin synthase?

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 Prostacyclin synthase.

Tags

  • EC 5.3.99
  • Enzymes of known structure
  • Genes on human chromosome 20
  • Heme enzymes

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