4-Methylumbelliferyl-alpha-glycosides of partially O-acetylated N-acetylneuraminic acids as substrates of bacterial and viral sialidases.
4-O-Acetylated, 7-O-acetylated, and 9-O-acetylated 4-methylumbelliferyl-alpha-N-acetyl-neuraminic acids (Neu4,5Ac2-MU, Neu5,7Ac2-MU, Neu5,9Ac2-MU) were tested as substrates of sialidases of Vibrio cholerae and of Clostridium perfringens. Both sialidases were unable to hydrolyse Neu4,5Ac2-MU. This compound at 1 mM concentration did not inhibit significantly the cleavage of Neu5Ac-MU, the best substrate tested. The 4-O-acetylated sialic acid glycoside is hydrolysed slowly by the sialidase from fowl plague virus. The relative substrate specificity, reflected in V/Km of the Vibrio cholerae sialidase is Neu5Ac-MU much greater than Neu5,7Ac2-MU approximately Neu5,9Ac2-MU and of the clostridial enzyme it is Neu5Ac-MU greater than Neu5,9Ac2-MU greater than Neu5,7Ac2-MU. The affinities of both enzymes for the side-chain O-acetylated sialic acid derivatives are higher than for Neu5Ac-MU. The artificial, well-defined substrates, described here, provide the opportunity to quantify the influence of sialic acid O-acetylation on the hydrolysis of sialoglycoconjugates without the side effects introduced by other parts of more complex glycans.
Biochemisches Institut Universität zu Kiel, Germany
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RG
Kleineidam
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K
Furuhata
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H
Ogura
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R
Schauer
D000107:Acetylation; D003016:Clostridium perfringens / Q000201:enzymology; D006027:Glycosides / Q000378:metabolism*; D006923:Hymecromone / Q000031:analogs & derivatives* / Q000378:metabolism; D009980:Influenza A virus / Q000201:enzymology; D007700:Kinetics; D009439:Neuraminidase / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism*; D013045:Species Specificity; D013379:Substrate Specificity; D014734:Vibrio cholerae / Q000201:enzymology
C030561:4-methylumbelliferyl glycosides; D006027:Glycosides; D012794:Sialic Acids; D006923:Hymecromone; D009439:Neuraminidase