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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...

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 name derives from the Greek κόλλα (kólla) (meaning "glue") and the suffix -γέν (-gen), denoting...

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 proteins or ISPs (2). AFGPs were originally discovered by DeVries and Wohlschlag in the blood of...