On the Specificity of Sialidase. Synthesis and Properties of N⁵-Acetyl-β-D-neuraminoylpeptides – AcNeu-Gly-OH, AcNeu-Glu-OH, AcNeu-Phe-OH — and the corresponding α-Ketosides

Catalytic mechanism of enzymic glycosyl transfer

“…Thus, it was shown 20 years ago that conversion of the carboxylate group to a primary alcohol or even the isoelectronic amide resulted in compounds which were not cleaved by the enzyme;206 neither were compounds in which the carboxylic acid group had been amidated with glycine, glutamic acid, or phenylalanine. 207 The 2,3-dehydro compound (XX) is a tight-binding inhibitor with a Kj on the order of 1 mM,208 as is its 8-epimer,209 whereas the 4-epimer208 and the 7-epimer209 are bound with Ki values on the order of 1 mM. Compound XX is a glycal, and by analogy with the interaction of other retaining glycosidases with the corresponding glycals, its hydration to AT-acetylneuraminic acid is expected.…”