Fatty acid metabolites, the eicosanoids, act as potent, short-lived hormone-like molecules. - ecosatetranoic acid (arachidonic acid) - imflamation - pain - fever - blood clotting affected - uterine contractions - sleep cycle

Lipids 2 Flashcards by Juan C

1st Lipid Functions

The vast bulk of cellular lipids (not counting triglycerides) serve as bilayer structural components.

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2nd lipid function

Lipids, especially acidic phospholipids, can serve as modulators of the activity of both soluble and membrane-bound proteins.

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3rd lipid function

Phosphatidylinositol serves as part of the tether of GPI-anchored membrane proteins.

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4th lipid function

Ether-linked glycerophospholipids, such as platelet activating factor, can act as molecular signals.

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5th lipid function

Derivatives of phosphatidylinositol act as intracellular second messengers in signal transduction pathways involved with many aspects of cellular regulation.

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6th lipid function

Fatty acid metabolites, the eicosanoids, act as potent, short-lived hormone-like molecules.

ecosatetranoic acid (arachidonic acid)
imflamation
pain
fever
blood clotting affected
uterine contractions
sleep cycle

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phospholips release

arachidonic acid (20:4)

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what are 2 pathways

Cyclic: prostaglandins and thromboxanes

linear:
- leukotrienes

-Lipoxins
Hepoxilins
Epi-lipoxins

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precursor to prodce 2 series… how to determine subscript

number of unsaturated bonds’

2 series can be derived:
- same as # of unsaturated
- # of unsaturated -2

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What can we make from palminate?

name essential FA

palmitate- stearate - Oleate

we cannot desaturate it beyond Oleate acid

-plants saturate it to make Linoleate acid (essential)

linolate- gamma linoleate –Elongation to Eicosatrienoate - desaturation to Arachodonate

Other path:
linoleate - alpha linoleate- other polyunsat FA’s

-other essential FA is alpha- linolenate

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omega carbon is which

the last one

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delta # is position of saturated bond from:

omega carbon

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not high yield:

how are elongation steps carried out?

The elongation steps, carried out in the smooth ER and mitochondria, involve the addition of acetyl groups from Coenzyme A (instead of ACP, as with stearate synthesis).

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what is a- linoleate

what is gamma linoleate

a-linolenate is an w-3 fatty acid

gamma-linolenate is an w-6 fatty acid

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w-3 fatty acid

90% reduction in Sudden Cardiac Death

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plants can change which omega FA?

9 to 6

6 to 3

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phospholipase if it cleaves FA at position 1

Phospholipase A1

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phospholipase if it cleaves FA at position 2

Phospholipase A2

sn2 position (related to ecosanoids)
releases FA

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phospholipase if it cleaves head group

Phospholipase D

phospholipase if it cleaves phosphohead group

phospholipase C

leaves diacylglycerol

rate limited step of ecosanoid synthesis

releasing of FA by phospholipase A2

-also targeted step of anti- imflamatory action of glucocorticoids

if phospholipase C cuts first what happens

minor pathway:

followed by diacylglycerol lipase to release the same thing arachidonic acid

cyclooxygenase (COX)

arachadonate is converted into PGH2 by a bifunctional enzyme, cyclooxygenase (COX). The conversion is a two step process. First molecular oxygen is introduced to produce PGG2 and then the peroxidase activity produces PGH2.

PGH2 is precursor for what

PGH2 is the precursor for the production of the prostaglandins and thromboxanes.

what blocks COX

The action of COX is blocked by aspirin and other NSAIDs.

Aspirin is what

Aspirin as a nonsteroidal antiinflammatory drug - blocks 1st reaction of COX - irreversible rxn

how does aspirin work on COX

serine residue acetylates OH to O-C=O-CH3

tylenol, ibuprofen, and Naproxen

other nsaids are reversible

COX1

House keeping - renal blood flow - protects from gastric acids - vascular homeostasis

Cox2

inducible in response to imflamation mediators

aspirin inhibits which isomer

both COX1 and COX 2

2nd gen NSAIDS

target COX 2 (VALINE VS ISOLEUCINE) drug cant get pass isoleucine but it can pass valine - Celecoxib - Rofecoxib 300 times more inhibition of COX 2 compared to COX 1

Thromboxin A2

strong platelet activity (made by platelets)

tylenol

may affect COX 3

prostacyclin

prevents clots from forming clots

aspirin shifts to prostacyclin side how

platelets irrevesible block platelet forming (no nucleus) - more thromboxane synthase endothelial cells have nucleus so they can make new cyclooxygenase - more prostacyclin synthase

pain relief

not explained ( many other pathways)

omega 3 FA

release more pentainoic acid - gives rise to PG H3 - PGI3 ALSO many other mechanism TAG's etc

Leukotriene biosynthesis begins with

the action of 5-lipoxygenase.

LTB4 promotes:

LTB4 promotes inflammation. Implicated in chronic inflammation associated with atherosclerosis.

cysteinyl-leukotrienes

LTC4, LTD4, and LTE4 -important mediators of immune-mediated inflammatory reactions of anaphylaxis.

Treatments for asthma include

antileukotriene agents that inhibit 5-lipoxygenase or the binding of the activator protein

lipoxins have opposing action to:

Interestingly, lipoxins have opposing action to LTC4. They inhibit bronchial spasms and have anti-inflammatory properties.

A new class of lipoxins are: how are they different? what is their synthesis triggered by? what actions do they have?

``` A new class of lipoxins, epi-lipoxins, differ in their stereochemistry. ``` Their synthesis is triggered by aspirin. They also have potent anti-inflammatory actions, further explaning the efficacy of aspirin

The Newest Players

Resolvins and Protectins * Potent anti-inflammatory action * Derived from the 20:5 and 22:6 w-3 fatty acids by a pathway involving aspirin-acetylated COX2 followed by 5-lipoxygenase. In the absence of aspirin-triggered COX2, EPA and DHA are acted on by 15-lipoxygenase to generate other anti-inflammatory agents. * It has been suggested by some that a dietary supplement of w-3 fatty acids, taken with aspirin, may reduce the clinical symptoms of several disease states, including inflammatory disorders (such as arthritis), cardiovascular disease, asthma, and certain cancers.