Prostanoid

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Information about Prostanoid

Prostanoid is the term used to describe a subclass of eicosanoids consisting of: the prostaglandins (mediators of inflammatory and anaphylactic reactions), the thromboxanes (mediators of vasoconstriction) and the prostacyclins (active in the resolution phase of inflammation.)

See also main articles at Prostaglandin, Prostacyclin and Thromboxane

Biosynthesis

Figure 1: Syntetic pathways from PGH₂ (the parent compound) to prostaglandins, prostacyclin and thromboxanes.

Cyclooxygenase (COX) catalyzes the conversion of the free essential fatty acids to prostanoids by a two-step process. In the first step, two molecules of O₂ are added as two peroxide linkages and a 5-member carbon ring is forged near the middle of the fatty acid chain. This forms the short-lived, unstable intermediate Prostaglandin G (PGG). One of the peroxide linkages sheds a single oxygen, forming PGH. (See diagrams and more detail at Cyclooxygenase). All other prostanoids originate from PGH, (as PGH₁, PGH₂, or PGH₃).

Figure 1 shows how PGH₂ (derived from Arachidonic acid) is converted:

By PGE synthetase into PGE (which in turn is converted into PGF)
By PGD synthetase into PGD
By Prostacyclin synthase into prostacyclin (PGI2)
By Thromboxane synthase into thromboxanes

The three classes of prostanoids have distinctive rings in the center of the molecule. They differ in their structures. The PGH compounds (parents to all the rest) have a 5-carbon ring, bridged by two oxygens (a peroxide.) The derived prostaglandins contain a single, unsaturated 5-carbon ring. In prostacyclins, this ring is conjoined to another oxygen-containing ring. In thromboxanes the ring becomes a 6-member ring with one oxygen.

See also

Essential fatty acid

• • [ e] Autacoids, unsaturated fatty acids: Eicosanoids
Prostanoids	Prostaglandins - Thromboxanes (A2, B2)
Other	Arachidonic acids - Eicosapentaenoic acid - Leukotrienes - Lipoxins

In biochemistry, eicosanoids are signaling molecules derived from omega-3 (ω-3) or omega-6 (ω-6) fats. They exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system.
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prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring.
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Inflammation (Latin, inflammatio, to set on fire) is the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants.
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MeSH D000707 Anaphylaxis is an acute systemic (multi-system) and severe Type I Hypersensitivity allergic reaction in humans and other mammals. The term comes from the Greek words ana (against) and phylaxis (protection).
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Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2.

Thromboxane is named for its role in clot formation (thrombosis).
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A vasoconstrictor, also vasopressor or simply pressor, is any substance that acts to cause vasoconstriction (narrowing of the lumena of blood vessels) and usually results in an increase of the blood pressure.
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Prostacyclin is a member of the family of lipid molecules known as eicosanoids. Epoprostenol (brand name Flolan) is a synthetic form of prostacyclin, approved by the FDA as a medicine in 1995.
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prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring.
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Prostacyclin is a member of the family of lipid molecules known as eicosanoids. Epoprostenol (brand name Flolan) is a synthetic form of prostacyclin, approved by the FDA as a medicine in 1995.
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Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2.

Thromboxane is named for its role in clot formation (thrombosis).
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Identifiers
Symbol PTGS2

Entrez 5743
HUGO 9605
OMIM 600262

RefSeq NM_000963
UniProt P35354
Other data
EC number 1.14.99.1
Locus Chr. 1 q25.2-25.3 Cyclooxygenase (COX) is an enzyme (EC 1.14.99.
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Identifiers
Symbol PTGS2

Entrez 5743
HUGO 9605
OMIM 600262

RefSeq NM_000963
UniProt P35354
Other data
EC number 1.14.99.1
Locus Chr. 1 q25.2-25.3 Cyclooxygenase (COX) is an enzyme (EC 1.14.99.
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Arachidonic acid (AA) is an omega-6 fatty acid 20:4(ω-6). It is the counterpart to the saturated arachidic acid found in peanut oil, (L. arachis – peanut.
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Identifiers
Symbol PTGES2
Alt. Symbols C9orf15

Entrez 80142
HUGO 17822
OMIM 608152

RefSeq NM_198939
UniProt Q9H7Z7
Other data

Locus Chr. 9 q34.
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Prostaglandin D2 synthase generates prostaglandin D2 from prostaglandin H2.

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Prostacyclin synthase is an enzyme involved in prostacyclin synthesis.

See also

Prostanoid

External links

MeSH prostacyclin+synthetase

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Prostacyclin is a member of the family of lipid molecules known as eicosanoids. Epoprostenol (brand name Flolan) is a synthetic form of prostacyclin, approved by the FDA as a medicine in 1995.
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Thromboxane-A synthase, also known as thromboxane synthetase, is an enzyme that catalyses the conversion of prostaglandin H₂ to thromboxane A₂. It is part of the cytochrome P450 system.
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Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2.

Thromboxane is named for its role in clot formation (thrombosis).
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A peroxide is a compound containing an oxygen-oxygen single bond. The simplest stable peroxide is hydrogen peroxide. Superoxides, dioxygenyls, ozones and ozonides compound are considered separately.
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Types of Fats in Food

Unsaturated fat
Monounsaturated fat
Polyunsaturated fat
Trans fat
Omega: 3, 6, 9

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Autacoids are biological factors that are primarily characterized by the effect they have upon smooth muscle. With respect to vascular smooth muscle, there are both vasoconstrictor and vasodilator autacoids.

Vasodilator autacoids can be released during periods of exercise.
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Types of Fats in Food

Unsaturated fat
Monounsaturated fat
Polyunsaturated fat
Trans fat
Omega: 3, 6, 9

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Types of Fats in Food

Unsaturated fat
Monounsaturated fat
Polyunsaturated fat
Trans fat
Omega: 3, 6, 9

..... Click the link for more information.

In biochemistry, eicosanoids are signaling molecules derived from omega-3 (ω-3) or omega-6 (ω-6) fats. They exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system.
..... Click the link for more information.

prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring.
..... Click the link for more information.

Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2.

Thromboxane is named for its role in clot formation (thrombosis).
..... Click the link for more information.

Thromboxane A2 is a thromboxane. It is generated from prostaglandin H2 by thromboxane-A synthase. It is also a major component of blood clots. Aspirin irriversibly inhibits platelet cyclooxygenase preventing the formation of prostaglandin H2, and therefore Thromboxane A2.
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Thromboxane B2 is the inactive product of thromboxane.

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Arachidonic acid (AA) is an omega-6 fatty acid 20:4(ω-6). It is the counterpart to the saturated arachidic acid found in peanut oil, (L. arachis – peanut.
..... Click the link for more information.

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