Catalysis by a new sialidase, deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm), initially forms a less stable alpha-anomer of 3-deoxy-D-glycero-D-galacto-nonulosonic acid and is strongly inhibited by the transition state analogue, 2-deoxy-2,3-didehydro-D-glycero-D-galacto-2-nonulopyranosonic acid, but not by 2-deoxy-2,3-didehydro-N-acetylneuraminic acid
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Author(s)
Terada, T
Kitajima, K
Inoue, S
Wilson, JC
Norton, AK
Kong, DCM
Thomson, RJ
vonItzstein, M
Inoue, Y
Year published
1997
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Deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm) is a new sialidase that has been induced and purified from Sphingobacterium multivorum. Catalysis by this new sialidase has been studied by enzyme kinetics and H NMR spectroscopy. V(max)/K(m) values determined for synthetic and natural substrates of KDNase Sm reveal that 4- methylumbelliferyl. KDN (KDNα2MeUmb, V(max)K(m) = 0.033 min ) is the best substrate for this sialidase, presumably because of its good leaving group properties. The transition state analogue, 2,3-didehydro-2,3-dideoxy-D- galacto-D-glycero-nonulosonic acid, is a strong competitive inhibitor of ...
View more >Deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm) is a new sialidase that has been induced and purified from Sphingobacterium multivorum. Catalysis by this new sialidase has been studied by enzyme kinetics and H NMR spectroscopy. V(max)/K(m) values determined for synthetic and natural substrates of KDNase Sm reveal that 4- methylumbelliferyl. KDN (KDNα2MeUmb, V(max)K(m) = 0.033 min ) is the best substrate for this sialidase, presumably because of its good leaving group properties. The transition state analogue, 2,3-didehydro-2,3-dideoxy-D- galacto-D-glycero-nonulosonic acid, is a strong competitive inhibitor of KDNase Sm (K(i) = 7.7 μM versus K(m) = 42 μM for KDNα2MeUmb). 2-Deoxy- 2,3-didehydro-N-acetylneuraminic acid and 2-deoxy-2,3-didehydro-N- glycolylneuraminic acid are known to be strong competitive inhibitors for bacterial sialidases such as Arthrobacter ureafaciens sialidase; however, KDNase Sm activity is not significantly inhibited by these compounds. This observation suggests that the hydroxyl group at C-5 is important for recognition of the inhibitor by the enzyme. Reversible addition of water molecule (or hydroxide ion) to the reactive sialosyl cation, presumably formed at the catalytic site of KDNase Sm, eventually gives rise to two different adducts, the α- and β-anomers of free 3-deoxy-D-glycero-D- galacto-nonulosonic acid. H NMR spectroscopic studies clearly demonstrate that the thermodynamically less stable α-form is preferentially formed as the first product of the cleavage reaction and that isomerization rapidly follows, leading to an equilibrium mixture of the two isomers, the β-isomer being the major species at equilibrium. Therefore, we propose that KDNase Sm catalysis proceeds via a mechanism common to the known exosialidases, but the recognition of the substituent at C-5 by the enzyme differs. 1 -1 1
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View more >Deaminoneuraminic acid residue-cleaving enzyme (KDNase Sm) is a new sialidase that has been induced and purified from Sphingobacterium multivorum. Catalysis by this new sialidase has been studied by enzyme kinetics and H NMR spectroscopy. V(max)/K(m) values determined for synthetic and natural substrates of KDNase Sm reveal that 4- methylumbelliferyl. KDN (KDNα2MeUmb, V(max)K(m) = 0.033 min ) is the best substrate for this sialidase, presumably because of its good leaving group properties. The transition state analogue, 2,3-didehydro-2,3-dideoxy-D- galacto-D-glycero-nonulosonic acid, is a strong competitive inhibitor of KDNase Sm (K(i) = 7.7 μM versus K(m) = 42 μM for KDNα2MeUmb). 2-Deoxy- 2,3-didehydro-N-acetylneuraminic acid and 2-deoxy-2,3-didehydro-N- glycolylneuraminic acid are known to be strong competitive inhibitors for bacterial sialidases such as Arthrobacter ureafaciens sialidase; however, KDNase Sm activity is not significantly inhibited by these compounds. This observation suggests that the hydroxyl group at C-5 is important for recognition of the inhibitor by the enzyme. Reversible addition of water molecule (or hydroxide ion) to the reactive sialosyl cation, presumably formed at the catalytic site of KDNase Sm, eventually gives rise to two different adducts, the α- and β-anomers of free 3-deoxy-D-glycero-D- galacto-nonulosonic acid. H NMR spectroscopic studies clearly demonstrate that the thermodynamically less stable α-form is preferentially formed as the first product of the cleavage reaction and that isomerization rapidly follows, leading to an equilibrium mixture of the two isomers, the β-isomer being the major species at equilibrium. Therefore, we propose that KDNase Sm catalysis proceeds via a mechanism common to the known exosialidases, but the recognition of the substituent at C-5 by the enzyme differs. 1 -1 1
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Journal Title
Journal of Biological Chemistry
Volume
272
Issue
9
Copyright Statement
© 1997 ASBMB. Currently published by Elsevier Inc; originally published by American Society for Biochemistry and Molecular Biology. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence (http://creativecommons.org/licenses/by-nc-nd/4.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, providing that the work is properly cited.
Subject
Chemical sciences
Biological sciences
Biomedical and clinical sciences
Science & Technology
Life Sciences & Biomedicine
Biochemistry & Molecular Biology
DEAMINATED NEURAMINIC ACID
RAINBOW-TROUT EGGS