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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...

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 powders occur frequently, as corn starch powder/dust is highly flammable (1). Such dust has tremendous...

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 of an alcohol is an organic compound with one or more hydroxyl groups (-OH) attached to a carbon, so...

By: Richard D. Cummings Cholesterol can be glycosylated, and indeed glucosylated cholesterol is common (1). In animal cells, it is a β-D-glucopyranoside derivative of cholesterol (GlcChol), which is generated through a ‘transglycosylation’ pathway in the lysosomes, by the enzymes glucocerebrosidase...

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 (1-4). All mammals make milk, of course, but the assortment of oligosaccharides beyond lactose is...

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 metabolism via GlcNAc, amino acids, and other intermediates to protein functions (1). The modification has...

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 proteins are synthesized using a template of short or long mRNAs; if they are then modified with attached...