Neuraminic acid was known first as sialic acid

Neuraminic acid, or sialic acid as it was first called, is a monosaccharide with nine carbons. It has a negative electric charge which gives compounds containing it a negative charge. This is useful for keeping molecules like red blood cells from getting to near to each other. The negative charge on the surface glycoproteins repels the red blood cell from each other or from the walls of blood vessels which also have compounds containing sialic acid.

Mature red blood cells have an active life for about seven days.  White blood cells remove older red blood cells and de-sialylation of the surface proteins is one way the older cells are identified. Cancer cells with the ability to produce excess surface sialyation may have an increased chance to metastasize and turn up somewhere else in the body. [13]

Our bodies need to be healthy and well enough nourished overall to keep the whole system working. The neuraminic acid is produced within our cells from other chemicals in a series of membranous channels called the endoplasmic reticulum and the golgi apparatus. The channels have embedded enzymes along the way somewhat like an assembly line in a factory. We can not just eat more sialic acid in our diet and have it show up on our cell surfaces – we have to be healthy enough and well enough nourished over all in order to be able to manufacture our own supply of sialic acid.

Therapeutic glycoproteins are being developed and the problem of just the right amount of sialylation is one of the hurdles being studied. [2] In addition to the negative charge sialic acid tends to stabilize and stiffen the protein portion of the glyco-compound.  The proteins that line vessels were described to be somewhat like bottle-brushes; the protein being somewhat like the sturdy wire handle of the brush and with the negatively charged sialic acid acting as bristles that electrically repel other molecules of sialic acid. [1]

/This article was originally posted on 8/21/2013./ /Disclaimer: Information presented on this site is not intended as a substitute for medical care and should not be considered as a substitute for medical advice, diagnosis or treatment by your physician./

More recent research from the scientists at the University of Zurich, regarding sialic acid, found an association between the presence of autoimmune disease and reduced levels of sialic acid on the individual’s antibodies, which are important for the body’s immune cells to be able to recognize and remove infected or foreign or decaying cells: “Specific Sugar in Antibodies Structure Determines the Risk of Autoimmune Diseases,” Oct. 7, 2015, [molecularbiologynews.org]

References:

  1. S.A. Brooks, M. V. Dwek, U. Schumacher, Functional and Molecular Glycobiology, (BIOS Scientific Publishers, Ltd., 2002), Amazon.
  2. Bork K, Horstkorte R, Weidemann W., “Increasing the sialylation of therapeutic glycoproteins: the potential of the sialic acid biosynthetic pathway.” J Pharm Sci. 2009 Oct;98(10):3499-508. doi: 10.1002/jps.21684.  [ncbi.nlm.nih.gov]
  3. R. T. Almaraz, et. al., “Metabolic Flux Increases Glycoprotein Sialylation: Implications for Cell Adhesion and Cancer Metastasis.” Mol Cell Proteomics. 2012 July; 11(7): M112.017558. Published online 2012 March 28. doi:  10.1074/mcp.M112.017558 [ncbi.nlm.nih.gov]

 

Glyco-compounds – essential sugar building blocks

Glyco- refers to glycogen which is sugar in a bigger starch form. Sugars are the building blocks of starches in the way that amino acids are the building blocks of proteins. The amino acids join together in straight chains like a string of beads or like letters in a word, a sentence, or a book. The straight protein chain can then fold into intricate shapes and form many chemicals.

However the sugars can actually connect to each other at each or most of the carbons in their structure – not just in one to one connections like beads on a necklace or letters in a sentence. Instead the sugars can connect at different ways and form many shapes like a Tinker Toy or Kinex building sets or like the words that can be built off of each other’s letters in the game Scrabble or Bananagrams.

Glucose and fructose are molecules that contain 6 carbons each but they are slightly different in shape – like mirror images – and our bodies need the glucose for building materials not the fructose. Fructose is an energy source (in other words it may be fattening if eaten in excess of the physical number of calories that are used up each day). Fructose is less useable as a building block – glucose is the form that is essential for our health. A molecule of table sugar is made from one molecule of glucose and one molecule of fructose.

Fucose, (6 C), mannose, (6 C), N-acetylglucosamine, (8 C), N-acetylneuraminic acid (11 C)  and galactose are also essential types of sugars with slightly different chemical forms. Some can be converted from one to another type but eating food sources may be better insurance (in case there are enzyme defects or other trace mineral deficiencies that may be reducing one’s ability to make enzymes).

The starches can code very complicated chemicals because the branching chain of sugar molecules can link together at more then one place – usually a bond can be formed at each of the carbon molecules in the molecule of sugar. So while there are fewer types of sugars than amino acids, each one can link together in several places and can create a more complex language in their branching shapes than is possible with the one to one connections of amino acids that from proteins.

The glyco-compounds form part of the jelly-like matrix of the glycocalyx layer. Proteins and lipids might be part of a glyco-compound. White blood cells can read and understand this glyco-language on the surfaces of other cells and allergens. Antigens and antibodies may not be effective if the diet doesn’t supply enough of the more unusual essential sugars.

Glyco-compounds dissolve in water better than the proteins or lipids (fats) would on their own. Glycolipids and glycoprotiens are nature’s way to help keep them suspended in water better. The sugar containing end of the compound dissolves in the watery fluid and helps keep the lipid or protein end moving along. The protein or fat by itself might separate from the fluid and stick to vessel walls or clot together into ungainly rafts of debris, which could lead to strokes or cardiovascular disease.

A life preserver keeps us suspended above water. The air trapped in the life preserver is keeping us mixed in the air environment and above the water while the body tries to sink. The floating masses of garbage in the oceans are suspended in a similar way.

Picture from: [thegoldenspiral.org/tag/environmental-terrorism/]

/Disclosure: This information is provided for educational purposes within the guidelines of fair use. While I am a Registered Dietitian this information is not intended to provide individual health guidance. Please see a health professional for individual health care purposes./