{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Eicosanoid Synthesis

Eicosanoid Synthesis - Molecular Biochemistry II Eicosanoid...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Eicosanoid Synthesis Copyright © 1999-2008 by Joyce J. Diwan. All rights reserved. Molecular Biochemistry II
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Prostaglandins and related compounds are collectively known as eicosanoids . Most are produced from arachidonic acid , a 20-carbon polyunsaturated fatty acid (5,8,11,14-eicosatetraenoic acid). The eicosanoids are considered " local hormones ." w They have specific effects on target cells close to their site of formation. w They are rapidly degraded, so they are not transported to distal sites within the body. But in addition to participating in intercellular signaling , there is evidence for involvement of eicosanoids in intracellular signal cascades .
Background image of page 2
w Examples of eicosanoids : prostaglandins prostacyclins thromboxanes leukotrienes epoxyeicosatrienoic acids. w They have roles in: inflammation fever regulation of blood pressure blood clotting immune system modulation regulation of sleep/wake cycle.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Arachidonic acid COOH PGE2 (prostaglandin E2) is an example of a prostaglandin, produced from arachidonic acid . COOH O HO OH PGE 2
Background image of page 4
PGE2 (prostaglandin E2). Prostaglandins all have a cyclopentane ring . w A letter code is based on ring modifications (e.g., hydroxyl or keto groups). w A subscript refers to the number of double bonds in the two side-chains. Thromboxanes are similar but have instead a 6-member ring . COOH O HO OH PGE 2
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Prostaglandin receptors: w Prostaglandins & related compounds are transported out of the cells that synthesize them. w Most affect other cells by interacting with plasma membrane G-protein coupled receptors . Depending on the cell type, the activated G- protein may stimulate or inhibit formation of cAMP , or may activate a phosphatidylinositol signal pathway leading to intracellular Ca++ release. w Another prostaglandin receptor, designated PPAR γ , is related to a family of nuclear receptors with transcription factor activity.
Background image of page 6
w Prostaglandin receptors are specified by the same letter code. E.g., receptors for E-class prostaglandins are EP . Thromboxane receptors are designated TP . w Multiple receptors for a prostaglandin are specified by subscripts (E.g., EP1, EP2, EP3, etc.). Different receptors for a particular prostaglandin may activate different signal cascades. Effects of a particular prostaglandin may vary in different tissues, depending on which receptors are expressed. E.g., in different cells PGE2 may activate either stimulatory or inhibitory or G-proteins, leading to either increase or decrease in cAMP formation.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Arachidonate is released from phospholipids by hydrolysis catalyzed by Phospholipase A2 . This enzyme hydrolyzes the ester linkage between a fatty acid and the OH at C2 of the glycerol backbone, releasing the fatty acid & a lysophospholipid as products. Phosphatidyl inositol
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 32

Eicosanoid Synthesis - Molecular Biochemistry II Eicosanoid...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon bookmark
Ask a homework question - tutors are online