Human melanoma cells express high levels of GM3 and GD3 gangliosides whereas normal melanocytes have only low levels of GD3 but maintain their expression of GM3. In order to understand the basis for this difference, the levels of the sialyltransferase that converts GM3 to GD3 (CMP-N-acetylneuraminic acid:GM3 sialyltransferase or GD3 synthase, EC 2.4.99.8) were analyzed in melanoma and other cel...

Gangliosides are cell-surface sialic acid containing glycolipids. They are found in high concentration on the surface of central nervous system cells. Gangliosides are believed to play a role in important biological events such as cell growth regulation, cell-cell adhesion, and malignancy.1-3 GM4 (1, Scheme 1) is structurally the simplest ganglioside and has been isolated as a minor component f...

Kelly, R. T. (Marquette University School of Medicine, Milwaukee, Wis.), D. Greiff, and S. Farmer. Neuraminidase activity in Diplococcus pneumoniae. J. Bacteriol. 91:601-603. 1966.-A method for the quantitation of neuraminidase in the presence of N-acetylneuraminic acid aldolase is described. The neuraminidase content of Diplococcus pneumoniae was found to be dependent on the media employed for...

Sialyltransferases transfer N-acetylneuraminic acid (Neu5Ac) from the common donor substrate of these enzymes, cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-Neu5Ac), to acceptor substrates. The enzymatic reaction products including sialyl-glycoproteins, sialyl-glycolipids and sialyl-oligosaccharides are important molecules in various biological and physiological processes, such as cell-c...

Lactose and neuramin lactose were produced by incubating subcellular particles from rat mammary gland in a system containing glucose, uridine diphosphate galactose, and cytidine monophosphate N-acetylneuraminic acid. The K, values for glucose in the synthesis of neuramin lactose were fairly constant for three similarly prepared enzyme preparations (0.25, 0.17, and 0.22 m&r), but were widely dis...

Lactose and neuramin lactose were produced by incubating subcellular particles from rat mammary gland in a system containing glucose, uridine diphosphate galactose, and cytidine monophosphate N-acetylneuraminic acid. The K, values for glucose in the synthesis of neuramin lactose were fairly constant for three similarly prepared enzyme preparations (0.25, 0.17, and 0.22 m&r), but were widely dis...

The identity of a novel form of sialyl-lactose found in milk of the echidna (Tachyglossus aculeatus) was investigated. The sialyl-lactose yielded equimolar amounts of N-acetylneuraminic acid and lactose during mild acid hydrolysis but was resistant to the action of a bacterial neuraminidase. A viral neuraminidase hydrolysed it to lactose plus a form of sialic acid that reacted positively with t...

Considerable interest has been manifest in the biosynthesis of protein-carbohydrate complexes as a result of the demonstration of their wide distribution in mammalian organs and body fluids. In recent years, significant progress has been made toward the elucidation of the chemical structure of plasma glycoproteins (l-5) in which the cardinal role of N-acetylglucosamine and N-acetylneuraminic ac...

Synthetic sialic acid analogues varying in the substitutents at position C-9 were analyzed for their ability to replace the natural receptor determinant for influenza C virus, N-acetyl-9-O-acetylneuraminic acid (Neu5,9Ac2). By incubation of erythrocytes with sialyltransferase and the CMP-activated analogues, the cell surface was modified to contain sialic acid with one of the following C-9 subs...