science

Plasmalogen

Plasmalogen is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Plasmalogen rather than just read about it. In short: Plasmalogens are a class of glycerophospholipid with a plasmenyl group linked to a lipid at the sn-1 position of the glycerol backbone. Plasmalogens are found in multiple domains of life, including mammals, invertebrates, protozoa, and anaerobic bacteria.

Key takeaways

Plasmalogen belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Plasmalogen to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Plasmalogen from memory before moving on to harder problems.

Reference excerpt

Plasmalogens are a class of glycerophospholipid with a plasmenyl group linked to a lipid at the sn-1 position of the glycerol backbone. Plasmalogens are found in multiple domains of life, including mammals, invertebrates, protozoa, and anaerobic bacteria. They are commonly found in cell membranes in the nervous, immune, and cardiovascular systems. In humans, lower levels of plasmalogens are studied in relation to some diseases. Plasmalogens are also associated with adaptations to extreme environments in non-human organisms.

Structure 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. Of these, the alkyl and alkenyl moiety in each case form an ether bond, which makes for two types of ether phospholipids, plasmanyl (alkyl moiety at sn-1), and plasmenyl (alkenyl moiety with vinyl ether linkage at sn-1). Plasmalogens are plasmenyls with an ester (acyl group) linked lipid at the sn-2 position of the glycerol backbone, chemically designated 1-0(1Z-alkenyl)-2-acyl-glycerophospholipids. The lipid attached to the vinyl ether at sn-1 can be C16:0, C18:0, or C18:1 (saturated and monounsaturated), and the lipid attached to the acyl group at sn-2 can be C22:6 ω-3 (docosahexaenoic acid) or C20:4 ω-6 (arachidonic acid), (both are polyunsaturated acids). Plasmalogens are classified according to their head group, mainly as PC plasmalogens (plasmenylcholines) and PE plasmalogens (plasmenylethanolamines). Plasmalogens should not be confused with plasmanyls.

Functions Plasmalogens are found in numerous human tissues, with particular enrichment in the nervous, immune, and cardiovascular systems. In human heart tissue, nearly 30–40% of choline glycerophospholipids are plasmalogens. 32% of the glycerophospholipids in the adult human heart, 20% in the brain and up to 70% of myelin sheath ethanolamine glycerophospholipids are plasmalogens. 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. In addition, they have been implicated as being signaling molecules and modulators of membrane dynamics.

History Plasmalogens were first described by Feulgen and Voit in 1924 based on studies of tissue sections. They treated these tissue sections with acid or mercuric chloride as part of a method to stain the nucleus. This resulted in the breakage of the plasmalogen vinyl-ether bond to yield aldehydes. In turn, the latter reacted with a fuchsine-sulfurous acid stain used in this nuclear staining method and gave rise to colored compounds inside the cytoplasm of the cells. Plasmalogens were named based on the fact that these colored compounds were present in the "plasmal" or inside of the cell.

Biosynthesis

Biosynthesis of plasmalogens begins with association of peroxisomal matrix enzymes glyceronephosphate O-acyltransferase (GNPAT) and alkylglycerone phosphate synthase (AGPS) on the luminal side of the peroxisomal membrane. These two enzymes can interact with each other to increase efficiency. Therefore, fibroblasts without AGPS activity have a reduced GNPAT level and activity. The first step of the biosynthesis is catalyzed by GNPAT. This enzyme acylates dihydroxyacetone phosphate at the sn-1 position. This is followed by the exchange of the acyl group for an alkyl group by AGPS. The 1-alkyl-DHAPdihydroxyacetone phosphate is then reduced to 1-O-alkyl-2-hydroxy-sn-glycerophosphate (GPA) by an acyl/alkyl-dihydroxyacetone phosphate reductase located in both peroxisomal and endoplasmatic reticulum membranes. All other modifications occur in the endoplasmatic reticulum. There an acyl group is placed at the sn-2 position by an alkyl/acyl GPA acyltransferase and the phosphate group is removed by a phosphatidic acid phosphatase to form 1-O-alkyl-2-acyl-sn-glycerol. Using CDP-ethanolamine a phosphotransferase forms 1-O-alkyl-2-acyl-sn-GPEtn. 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. The protein corresponding to plasmanylethanolamine desaturase has been identified and is called CarF in bacteria and PEDS1 (TMEM189) in humans (and animals). Plasmenylcholine is formed from 1-O-alkyl-2-acyl-sn-glycerol by choline phosphotransferase. As there is no plasmenylcholine desaturase choline plasmalogens can be formed only after hydrolysis of ethanolamine plasmalogens to 1-O-(1Z-alkenyl)-2-acyl-sn-glycerol that can be modified by choline phosphotransferase and CDP choline.

Pathology Peroxisome biogenesis disorders are autosomal recessive disorders often characterized by impaired plasmalogen biosynthesis. In these cases, the peroxisomal enzyme GNPAT, necessary for the initial steps of plasmalogen biosynthesis, is mislocalized to the cytoplasm where it is inactive. 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. In such cases, both copies of the GNPAT or AGPS gene must be mutated in order for disease to manifest. Unlike the peroxisome biogenesis disorders, other aspects of peroxisome assembly in RCDP2 and RCDP3 patients are normal as is their ability to metabolize very long chain fatty acids. Individuals with severe plasmalogen deficiencies frequently show abnormal neurological development, skeletal malformation, impaired respiration, and cataracts.

Deficits in plasmalogen levels contribute to pathology in Zellweger syndrome. Plasmalogen-knockout mice show similar alterations like arrest of spermatogenesis, development of cataract and defects in central nervous system myelination. Plasmalogen alkyl chains have been shown to promote or inhibit the cell death from ferroptosis, depending on their degree of saturation.

During inflammation 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. Several researchers are currently investigating the impact of chlorinated lipids on pathology.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Plasmalogen

Start with the simplest possible case. Write down what Plasmalogen claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Plasmalogen before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Plasmalogen ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Plasmalogen

In research: Plasmalogen appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Plasmalogen in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Plasmalogen is common in secondary-school and first-year university syllabi. It links to neighbouring topics Phospholipids, so understanding it makes those chapters shorter.
In everyday life: Look for Plasmalogen outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Plasmalogen” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Plasmalogen in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Plasmalogen means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Plasmalogen out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Plasmalogen in simple terms?

Why does Plasmalogen matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Plasmalogen?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Plasmalogen.