Chemical Glycoprotein Synthesis

Yasuhiro Kajihara1, Masumi Murakami1, and Carlo Unverzagt2 

1 Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan 2Bioorganische Chemie, Universitdt Bayreuth, Bayreuth, Germany 

Glycochemical Synthesis Strategies and Applications, First Edition. 

Edited by Shang-Cheng Hung and Medel Manuel L. Zulueta. 

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Enzyme Catalysis, Chemical Strategies for Glycan Biosynthesis in Mammals Glycosyltransferases, Chemistry of Glycolipids, Synthesis of Glycopeptides and Glycoproteins, Synthesis of... 

For this purpose, Ag zeolite and Ag, developed by Garegg25 and Paulsen,26 respectively, have been widely employed (Scheme 7.6). Reactions using these activators have found practical use in synthetic studies on glycoprotein glycans and glycolipids. For instance, Paulsen reported the chemical synthesis of the core pentasaccharide structure 6 common to all types of Asn-linked glycans, using the Ag... 

N-Acetvlneuraminic Acid Aldolase. A new procedure has also been developed for the synthesis of 9-0-acetyl-N-acetylneuraminic acid using the aldolase catalyzed reaction methodology. This compound is an unusual sialic acid found in a number of tumor cells and influenza virus C glycoproteins (4 ). The aldol acceptor, 6-0-acetyl-D-mannosamine was prepared in 70% isolated yield from isopropenyl acetate and N-acetyl-D-mannosamine catalyzed by protease N from Bacillus subtilis (from Amano). The 6-0-acetyl hexose was previously prepared by a complicated chemical procedure (42.) The target molecule was obtained in 90% yield via the condensation of the 6-0-acetyl sugar and pyruvate catalyzed by NANA aldolase (Figure 6). With similar procedures applied to KDO, 2-deoxy-NANA and 2-deoxy-2-fluoro-NANA were prepared from NANA. 

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