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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 animals (1), and many different human and animal parasites (2). Sphingolipids were originally discovered...

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 expressed within the glycoproteins in a cell. N-glycans are those linked to asparagine (Asn) residues in the...

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). There are dozens of rare sugars that are recently gaining attention in regard to nutrition, metabolism...

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) glycoproteins. This accepted process was taken to indicate that no glycosylated proteins occurred in...

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, glycohydrolases, transporters, and chaperones. Mutations in several of these X-linked genes, either heritable or...

By: Richard D. Cummings In plants, glucose is produced from carbon dioxide (CO 2) and water through photosynthesis, which generates oxygen (O 2) as a byproduct. Without sunlight/photosynthesis, the Calvin Cycle, along with probably the most important enzyme in the world - RuBisCo (Ribulose-1,5...

By: Richard D. Cummings One of the smallest known naturally-occurring glycoprotein in mammals is likely to be CD24, also known as nectadrin. Although it behaves in analyses as a 23-60 kDa glycoprotein, the glycoprotein from mice has only 27 amino acids (human protein has 30 amino acids) (1-3)...

By: Richard D. Cummings One of the most complex polysaccharides in nature is pectin, found in plant cell walls (1,2). Pectin is a family of galacturonic acid-rich polysaccharides that includes homogalacturonan (HG), rhamnogalacturonan I (RG-I), and the substituted galacturonans rhamnogalacturonan II...

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 Gram negative (1). This form of cellulose can be highly purified compared to preparations of plant...

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). The keyhole limpet is a giant aquatic snail (gastropod) with a cone-shaped shell (shell length can...