PubMed · 4264352
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S A Plotkin. 1972. Antibiotics, 1972.. https://doi.org/10.1177/000992287201101205
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The syntheses are described of 6-amino-6-deoxymaltose (2), the 6-amino-6-deoxy (4), 6'-amino-6'-deoxy (6), and 6"-amino-6"-deoxy (8) derivatives of maltotriose, and the methyl alpha- (10) and beta-glycoside (12) and the 1-deoxy derivative (16) of 4. The Ki values (microM) of these competitive inhibitors of porcine pancreatic alpha-amylase were: 2, 88; 4, 1.9; 6, 2.0; 8, 175; 10, 360; 12, 9000; 16, 7600 (cf. 1800 for maltotriose and 3000 for methyl alpha-maltotrioside). The low values for 4 and 6 reflect reinforcement of the normal binding by ionic attraction and, possibly, interaction of the reducing end groups with the protein.
Inhibition of 3-deoxy-manno-octulosonate cytidylytransferase (CMP-KDO transferase; EC 2.7.7.38) by 8-amino-2,6-anhydro-3,8-dideoxy-D-glycero-D-talo-octonic acid (NH2dKDO) halts the growth of Gram-negative bacteria by depriving the cells of the 3-deoxy-D-manno-2-octulosonate required for the biosynthesis of the core region of the lipopolysaccharide components of the outer membrane. Low levels of this inhibitor increase the vulnerability of Escherichia coli to hydrophobic antibiotics, detergents, the complement-mediated antibacterial activity of serum, phagocytosis, and enhance the rate at which bacteria are cleared from the mouse bloodstream.
We have metabolically labeled the human pancreatic tumor cell line PANC-1 with high specific activity tritiated sugar precursors to study the expression of glycosphingolipids by this cell type. We have used a combination of detergent solubilization, exhaustive protease digestion, ceramide glycanase digestion, and reverse-phase chromatography to isolate glycosphingolipid-derived oligosaccharides specifically labeled in their component sugars. A significant proportion of the oligosaccharides derived from polar glycosphingolipids were of high molecular mass (greater than 2000 Da). The results of compositional studies, lectin affinity chromatography, and methylation analysis suggested that this high molecular weight fraction consists of lactosaminoglycan type oligosaccharides derived from polyglycosylceramides. There are on average three beta 1-6 linked N-acetyllactosamine branches attached to the polylactosamine backbone in this type of glycosphingolipid-derived oligosaccharide. The majority of the oligosaccharides also contain 1-2 mol of sialic acid that are linked alpha 2-3 to penultimate galactose. The results indicate that PANC-1 cells, like human colorectal tumor cells, express highly extended neolacto type glycosphingolipids. However, the lactosaminoglycan sequences are highly branched, unlike those associated with colorectal tumor cells.