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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 While the N-glycosylation sequon N-X-S/T in glycoproteins of plants, fungi, and animals, is well known, there are many reports of alternative sequons for N-glycosylation in animals (1), including the sequences -N-X-C- (2-4), -N-X-V- (5,6), -N-V-E- (7), -N-X-A- (8), -N-X-G- (9...

By: Richard D. Cummings L-Ascorbic acid, vitamin C, is termed a ‘sugar acid’ or ‘acidic sugar’, and is a derivative of glucose with a carboxyl group at C1 (1). In mammals, UDP-glucuronic acid is the source of D-glucuronic acid, the precursor to vitamin C (2). Vitamin C is sometimes referred to as a...

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-acetylneuraminic acid (Neu5Ac) also termed sialic acid. The name sialic acid derives from its discovery in...

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 notable ones that do, as discussed below. In addition, sialic acid is not generated nor found in...

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 acid (UDP-GlcA) as a donor and add GlcA to a tremendous variety of aglycone hydrophobic compounds...

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/mL. It was discovered in 1950 by Tamm and Horsfall in their studies on compounds in urine that could...

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-acetylglucosaminyltransferase (OGT) that adds O-GlcNAc to Ser/Thr residues of proteins in...

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...