The activities of glycosyltransferases and sialidases, together with the ganglioside content and distribution, have been extensively studied in mammals, while the informations on tissues of other animals, including amphibian, are scarce. In this paper we present data on the activities of SAT-1, SAT-2, SAT-4, SAT-5, GlcNAcT-1, GalNAcT-1, GalT-6, and sialidases studied in Xenopus laevis embryos at different stages of development. The highest activity was found at days 4 and 5 of embryogenesis for glycosyltransferases and sialidases respectively; a tentative correlation between the in vitro activity of these enzymes and the content of neutral and acidic glycolipids is discussed.
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http://dx.doi.org/10.1023/a:1006891414663 | DOI Listing |
Angew Chem Int Ed Engl
December 2024
Key Laboratory of Marine Drugs of Ministry of Education, Shandong Key Laboratory of Glycoscience and Glycotherapeutics, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China.
Owing to the inaccessibility of β1-4-N-acetylgalactosaminyltransferase for direct glycan chain elongation, the enzymatic synthesis of 0-series gangliosides with extended backbones has not been explored. In this study, sialic acid was enzymatically introduced as an auxiliary group to overcome the limitation of substrate specificity of Campylobacter jejuni β1-4-N-acetylgalactosaminyltransferase (CjCgtA) to achieve the synthesis of desired extended 0-series ganglioside core structures, and the sialic acid auxiliary group could be removed by sialidase at appropriate stages. A bacterial α2-6-sialyltransferase from Photobacterium damselae (Pd2,6ST) exhibited unexpected acceptor substrate specificity for 0-series ganglioside core structures, providing ready access to complex gangliosides bearing the sialyl N-acetylgalactosamine unit.
View Article and Find Full Text PDFBiochem Biophys Res Commun
December 2024
Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 770-8514, Japan. Electronic address:
Chronic exposure to arsenic has been shown to induce carcinogenesis in multiple organs, but the mechanisms underlying the multi-organ carcinogenicity of arsenic remain unknown. We here examined whether arsenic affects the amount of sialic acid on the cellular surface of immortalized HaCaT cells rather than cancerous cells to clarify the process of arsenic-induced carcinogenesis, since sialic acid is known to assist cancer cells in suppressing attacks by natural killer (NK) cells. Our results indicated that exposure to arsenite (As(III)) increases the amounts of sialic acid on the cell surface of HaCaT cells.
View Article and Find Full Text PDFChembiochem
December 2024
Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.
Glycoconjugates are a vast class of biomolecules implicated in biological processes important for human health and disease. The structural complexity of glycoconjugates remains a challenge to deciphering their precise biological roles and for their development as biomarkers and therapeutics. Human glycoconjugates on the outside of the cell are modified with sialic (neuraminic) acid residues at their termini.
View Article and Find Full Text PDFCarbohydr Polym
November 2024
Key Laboratory of Digestive Diseases, Lanzhou University Second Hospital, Lanzhou, China; Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, China. Electronic address:
Sialylation, a crucial post-translational modification of glycoconjugates, entails the attachment of sialic acid (SA) to the terminal glycans of glycoproteins and glycolipids through a tightly regulated enzymatic process involving various enzymes. This review offers a comprehensive exploration of sialylation within the gut, encompassing its involvement in mucosal protection and its impact on disease progression. The sialylation of mucins and epithelial glycoproteins contributes to the integrity of the intestinal mucosal barrier.
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
July 2024
Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria.
Background: Type 1 (T1D) and type 2 (T2D) diabetes lead to an aberrant metabolism of sialoglycoconjugates and elevated free serum sialic acid (FSSA) level. The present study evaluated sialidase and sialyltranferase activities in serum and some organs relevant to diabetes at early and late stages of T1D and T2D.
Methods: Sialic acid level with sialidase and sialyltransferase activities were monitored in the serum, liver, pancreas, skeletal muscle and kidney of diabetic animals at early and late stages of the diseases.
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