Phospholipids

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Phospholipids, or glycerol phospholipids, are derivatives of phosphatidic acid (glycerol-3-phosphoric acid). According to the type of substituent attached to phosphatidic acid, phospholipids are further divided into:

Phosphatidylcholines (lecithins)
Phosphatidylethanolamines (kephalins)
Phosphatidylserines
Plazmalogens
Phosphatidylinositols

Phosphatidylcholines (lecithins)[edit | edit source]

Phosphatidylcholine

They contain choline, a quaternary nitrogen base
They are a part of the cell membrane
A large part of the body's supply of choline (important for the transmission of nerve impulses)
Waxy, colorless compounds with hydrophilic and hygroscopic features
They form colloid solutions in the water, create internal salts, reduce surface tension, good emulsifying agents
Easily hydrolyzed in the body due to the action of phospholipases
Dipalmitoyllecithin – surfactant

For more information see Phosphatidylcholine.

Phosphatidylethanolamines (kephalins)[edit | edit source]

They contain ethanolamine bound by an ester bond to the second acid group of phosphoric acid
Similar character as phosphatidylcholines

Phosphatidylserine[edit | edit source]

Phosphatidylserine

It contains serine amino acid
It is found in most tissues

Plazmalogens[edit | edit source]

The fatty acid is replaced at position 1 by an ether-linked higher unsaturated alcohol
Similar to lecithins and kephalins
Synthesized on peroxisomes by desaturation of 3-phosphoethanolamine derivatives (requires molecular oxygen, cytochrome b5, NADPH+ + H+ for the synthesis)
There are 3 types of plasmalogens: choline, ethanolamine, serine
Most of the phospholipids in mitochondria are plasmalogens
Choline plasmalogen, the so-called platelet-activating factor (PAF), is a mediator of hypersensitivity, acute inflammatory reaction and anaphylactic shock. The IgE antigen stimulates its production. When PAF is released, platelet aggregation and serotonin secretion occur

Phosphatidylinositol[edit | edit source]

Phosphatidylinositol

They contain inositol, a sugar alcohol
Part of cell membranes, where they significantly influence its permeability
A source of arachidonic acid, which is the starting material for the formation of eicosanoids
Important for the transport of fats by blood and lymph
After stimulation by a certain hormone, phosphatidylinositol-4,5-bisphosphate is split into diacylglycerol and inositol triphosphate - these substances act as an internal signal or second messenger

Links[edit | edit source]

External links[edit | edit source]

Lipids (english wikipedia)

Used literature[edit | edit source]

MATOUŠ, Bohuslav. Základy lékařské chemie a biochemie. 2010. edition. Galen, 2010. 0 pp. ISBN 978-80-7262-702-8.

MURRAY, Robert K. Harperova biochemie. 2. edition. H&H, 2002. 871 pp. ISBN 80-7319-013-3.