Plasmalogen

Glycerophospholipids of biochemical relevance are divided into three subclasses based on the substitution present at the sn-1 position of the glycerol backbone: acyl, alkyl and alkenyl.

Plasmalogens are plasmenyls with an ester (acyl group) linked lipid at the sn-2 position of the glycerol backbone,[5][6] chemically designated 1-0(1Z-alkenyl)-2-acyl-glycerophospholipids.

[11] Although the functions of plasmalogens have not yet been fully elucidated, it has been demonstrated that they can protect mammalian cells against the damaging effects of reactive oxygen species.

After dehydrogenation at the 1- and 2-positions of the alkyl group by an electron transport system and plasmanylethanolamine desaturase the vinyl ether bond of plasmalogens is finally formed.

In addition, genetic mutations in the GNPAT or AGPS genes can result in plasmalogen deficiencies, which lead to the development of rhizomelic chondrodysplasia punctata (RCDP) type 2 or 3, respectively.

Individuals with severe plasmalogen deficiencies frequently show abnormal neurological development, skeletal malformation, impaired respiration, and cataracts.

[20] Plasmalogen-knockout mice show similar alterations like arrest of spermatogenesis, development of cataract and defects in central nervous system myelination.

[24][25] During inflammation, neutrophil-derived myeloperoxidase produces hypochlorous acid, which causes oxidative chlorination of plasmalogens at the sn-1 chain by reacting with the vinyl ether bond.

[17] Plasmalogens have been shown to have a complex evolutionary history based on the fact that their biosynthetic pathways differ in aerobic and anaerobic organisms.

[35] Recently, it has been demonstrated that the red blood cells of humans and great apes (chimpanzees, gorillas and orangutans) have differences in their plasmalogen composition.

Gene expression data from all these species caused the authors to speculate that other human and great ape cells and tissues differ in plasmalogen levels.

Plasmalogens form a major component in the cell membranes of deep-sea animals like the comb jelly, enhancing molecular resistance to high pressure.