6857-21-2Relevant articles and documents
2-DEOXY-1,3,4,5,6-PENTA-O-METHYL-2-(N-METHYLACETAMIDO)-D-GLUCITOL AND DERIVATIVES UNDERGO C-METHYLATION AT THE N-METHYLACETAMIDO GROUP ON REPEATED HAKOMORI METHYLATION
Zaehringer, Ulrich,Rietschel, Ernst Theodor
, p. 81 - 88 (1986)
After Hakomori methylation of 2-acetamido-2-deoxy-D-glucitol, the expected 2-deoxy-1,3,4,5,6-penta-O-methyl-2-(N-methylacetamido)-D-glucitol (3) was identified by g.l.c.-m.s. as the major product, and two minor products, 2-acetamido-2-deoxy-1,3,4,5,6-penta-O-methyl-D-glucitol (2) and 2-deoxy-1,3,4,5,6-penta-O-methyl-2-(N-methylpropionamido)-D-glucitol (4), were present.The proportions and yields of these products were dependent on the reagent (sodium or potassium hydride) used for the preparation of the methylsulfinylmethanide.On Hakomori methylation of 2 and 3, the N-methylpropionamido (4), N-methylisobutyramido, and traces of the N-methylpivalamido derivatives of 2-deoxy-1,3,4,5,6-penta-O-methyl-D-glucitol were formed.Using trideuteriomethyl iodide for methylation (e.g., of 3), it was found by g.l.c.-m.s. that the newly introduced methyl group(s) were located at the β-carbon of the N-methylacetamido group.Analogous results were obtained with 2-deoxy-4-O--1,3,5,6-tetra-O-methyl-2-(N-methylacetamido)-D-glucitol.
Sialic acid metabolic engineering of breast cancer cells interferes with adhesion and migration
Gnanapragassam, Vinayaga Srinivasan,Horstkorte, Rüdiger,Nagasundaram, Manimozhi
, (2020/06/26)
Breast cancer is the most frequent cancer diagnosed in women and the second most common cancer-causing death worldwide. The major problem around the management of breast cancer is its high heterogeneity and the development of therapeutic resistance. Therefore, understanding the fundamental breast cancer biology is crucial for better diagnosis and therapy. Protein sialylation is a key posttranslational modification of glycoproteins, which is also involved in tumor progression and metastasis. Increased expression of sialic acids (Sia) can interfere in receptor-ligand interactions and might protect tumor cells from the immune system. Furthermore, Sia content on the cell membrane plays a role in cancer resistance towards chemo- and radiation therapy. In this study, we glycoengineered MCF-7 breast cancer cells using a series of non-natural Sia precursors, which are prolonged in their acyl side chain. We observed a significant reduction in the natural Sia (N-Acetylneuraminic acid) expression after cultivation of MCF-7 cells with these Sia precursors. In addition, the expression of polySia, a unique glycosylation of the neural cell adhesion molecule NCAM, which interferes with cell adhesion, was decreased. We conclude that sialic acid engineering i) opens up novel opportunities to study the biological role of Sia in breast cancer and ii) provides a toolbox to examine the sialic acid-dependent complex cellular alterations in breast cancer cell biology.
Highly efficient and selective biocatalytic production of glucosamine from chitin
Lv,Laborda,Huang,Cai,Wang,Lu,Doherty,Liu,Flitsch,Voglmeir
supporting information, p. 527 - 535 (2017/08/15)
N-Acetyl glucosamine (GlcNAc) is one of the most abundant biomolecules on Earth and is cheaply available from chitin, a major component of crustaceans. The key step in the conversion of GlcNAc to high-value products is the de-N-acetylation to glucosamine, in itself a valuable dietary supplement that is produced at over 29:000 tons scale per annum by chemical hydrolysis, a process that requires harsh reaction conditions and leads to side products requiring separation. Here, we report for the first time the isolation and characterisation of an enzyme, a deacetylase from Cyclobacterium marinum that is able to catalyse the highly selective quantitative hydrolysis of GlcNAc to glucosamine under mild reaction conditions. This enzyme is small (38 kDa), is easily obtainable by heterologous expression in E. coli, has high turnover rates (kcat=61 s-1), tolerates high substrate concentrations (over 100 g L-1) and can be repeatedly re-used as an immobilised catalyst. When coupled with chitinase, the high selectivity of the enzyme for GlcNAc over other biomolecules allowed one-pot extraction of glucosamine from crude solid mushroom fractions containing chitin, thus allowing for alternative production of glucosamine from non-animal sources, of benefit to consumers with crustacean allergies and vegan diets. We suggest that the deacetylase fills an important gap in the sustainable exploitation of GlcNAc and chitin.
