title: Synthesis of CMP-9''-modified-sialic acids as donor substrate analogues for mammalian and bacterial sialyltransferases.
abstract: Cytidine-5'-monophospho-sialic acid (CMP-Neu5Ac) derivatives bearing a phenyl group in which the tether length between the phenyl group and the 9-position of Neu5Ac varied were synthesized and evaluated as substrates for sialyltransferases. In the synthesis of the compounds, a coupling reaction between methyl 5-acetamido-4,7,8-tri-O-acetyl-9-azido-3,5,9-trideoxy-beta-D-glycero-D-galacto-2-nonulopyranosonate and 2-cyanoethyl 2',3'-O,N4, triacetylcytidine-5'-yl N,N-diisopropylphosphoramidite was carried out and the phosphite derivative thus obtained was oxidized and then deprotected to yield CMP-9''-azido-Neu5Ac. Modification of the 9-amino group prepared by reduction of the azido groups was performed by the use of several phenyl-substituted alkylcarboxylic acid derivatives. Using these CMP-9''-modified-Neu5Ac analogues bearing the phenyl-substituted alkyl-amide group, sialyltransferase assays were performed with both rat liver alpha-(2-->6)-sialyltransferase and Photobacterium alpha-(2-->6)-sialyltransferase. These 9-modified analogues could be transferred to disaccharide acceptors, and a practical enzymatic synthesis using CMP-9''-modified-Neu5Ac yielded sialoside analogues and sialylglycoproteins in good yield. These experiments demonstrate that the Photobacterium sialyltransferase can be used in the synthesis of sialoside analogues having a large substituent at the 9-position of Neu5Ac.
authors.affiliation: International Graduate School of Arts and Sciences, Yokohama City University, 22-2, Seto, Yokohama 236-0027, Japan. kajihara@yokohama-cu.ac.jp
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kajihara
authors.forename: Toshimi
authors.initials: T
authors.lastname: Kamitani
authors.forename: Reiko
authors.initials: R
authors.lastname: Sato
authors.forename: Naoki
authors.initials: N
authors.lastname: Kamei
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Ryo
authors.initials: R
authors.lastname: Okamoto
authors.forename: Thoru
authors.initials: T
authors.lastname: Sakakibara
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuji
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D001419:Bacteria / Q000201:enzymology; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D008322:Mammals; D008958:Models, Molecular; D012799:Sialyltransferases / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid; D012799:Sialyltransferases