Interesting Facts About Glycans

By: Richard D. Cummings

Over 500 different post-translational modifications (PTMs) of amino acids in proteins are now recognized (1). Among the many different types of protein modifications...

By: Richard D. Cummings 

It is well known that human cells produce a wide variety of glycans in the processes of biosynthesis (anabolism), and that cells also produce many glycosidases (glycoside...

By: Richard D. Cummings

We think of glycolysis and the fermentation of glucose as being universal.  This common glycolytic pathway in animals is termed the Embden-Meyerhof-Parnas pathway, which...

By: Richard D. Cummings

Five of the most famous giant polysaccharides produced by microbes, plants, and animals are peptidoglycan, starch, cellulose, chitin, and hyaluronic acid (hyaluronan, HA). ...

By: Richard D. Cummings

In plants, glucose is produced from carbon dioxide (CO₂) and water through photosynthesis, which generates oxygen (O₂) as a byproduct.  Without sunlight/photosynthesis, the...

By: Richard D. Cummings

Until a few years ago it was believed that mitochondria do not contain glycoproteins.  However, mitochondria contain a variant form of the enzyme UDP-GlcNAc: polypeptide O-β-N...

By: Richard D. Cummings

I am not aware of studies that have directly and quantitatively determined the number of glycoprotein molecules in a cell or the actual number of N-glycan molecules...

By: Richard D. Cummings

Sugar alcohols are a reduced form of a sugar in which the aldehyde or ketone is replaced with an -OH, and sometimes referred to as polyols.  Strictly speaking, the definition...

By: Richard D. Cummings

Among the 900-1,400 genes on the human X chromosome (1, 2)[1], there are many genes important in the metabolism of glycomolecules, including glycosyltransferases...

By: Richard D. Cummings

In the mid 1980s it was strongly believed that all glycosylated proteins arose within the secretory pathway, which generated both secreted and membrane-bound (plasma membrane)...

By: Richard D. Cummings

Most, if not all, of the carbohydrates and glycans in animals are reducing glycans in their free form, either as they are generated, e.g., milk sugars, or upon release from...

By: Richard D. Cummings

Antifreeze glycoproteins (AFGPs) are named due to their unusual ability to inhibit ice formation (1). Antifreeze glycoproteins and proteins are also called ice structuring...

By: Richard D. Cummings

We usually think of polysaccharides as being relatively inert.  However, dust explosions in grain elevators and in areas of high density of corn starch or polysaccharide...

By: Richard D. Cummings

Glycosphingolipids (GSLs) are sphingolipids, such as ceramide, to which sugars are linked.  They are found in virtually all organisms including bacteria, fungi, plants, and...

By: Richard D. Cummings

The major urinary glycoprotein is the Tamm-Horsfall protein (THP), also named uromodulin (Umod), and encoded by UMOD (1-4). Its concentration in urine can be as high as 1-2 mg...

By: Richard D. Cummings

The endoplasmic reticulum (ER) of many types of cells contain members of a family of UDP-glucuronosyltransferases (UGTs).  These enzymes utilize uridine diphosphate glucuronic...

By: Richard D. Cummings

One of the most unusual glycoproteins and one used commonly in biological research and immunology is KLH, which is derived from the giant keyhole limpet (Megathura crenulata)...

By: Richard D. Cummings

While plant cellulose is very famous, many commercial products containing cellulose actually use bacterial cellulose.  It is often a part of bacterial biofilms, typically of...

By: Richard D. Cummings

The definition of a rare sugar is a monosaccharide that is found in small quantities relative to more common sugars in nature, e.g., glucose and N-acetylglucosamine (1-3). ...

By: Richard D. Cummings

Sialic acid is a nonose (9-carbon) monosaccharide found in many organisms.  All vertebrates have sialic acid, while most invertebrates do not have sialic acid, but there are...

By: Richard D. Cummings

Collagen is the most common and abundant glycoprotein in animals (1).  Even sponges have collagen (termed spongin) and it is glycosylated much like mammalian collagen.  Its...

By: Richard D. Cummings

Many different monosaccharides from trioses (3-carbon) to decoses (10-carbon) and above are found in nature (1).  The most famous nonose (9-carbon) in human glycans is N...

By: Richard D. Cummings

A peptide is usually considered to be a linkage of 2 to 50 amino acids via peptide bonds, and proteins are larger than 50 or so amino acids.  In animal cells, peptides and...

By: Richard D. Cummings

O-GlcNAc is a major reversible modification of Ser/Thr residues found on thousands of intracellular glycoproteins in the nucleus, cytoplasm, and mitochondria, and links...

By: Richard D. Cummings

The disaccharide lactose, Galβ1-4Glc, is found only in the milk of mammals, and so far, it and extended milk oligosaccharides derived from it, are found nowhere else in nature...