2′,3′‐Dialdehydo‐UDP‐<i>N</i>‐acetylglucosamine inhibits UDP‐<i>N</i>‐acetylglucosamine 2‐epimerase, the key enzyme of sialic acid biosynthesis

Abstract

Sialic acids comprise a family of terminal sugars essential for a variety of biological recognition systems. UDP-N-acetylglucosamine 2-epimerase catalyzes the first step of their biosynthesis. Periodate-oxidized UDP-N-acetylglucosamine, namely 2',3'-dialdehydo-UDP-alpha-D-N-acetylglucosamine, was found to be an effective inhibitor of this enzyme, compared with the periodate oxidation products of compounds such as UDP, uridine or methyl riboside. It bound covalently to amino acids in the active site causing an irreversible inhibition. This compound may therefore represent a basis for the synthesis of potent inhibitors of UDP-N-acetylglucosamine 2-epimerase and, as a consequence, of the biosynthesis of sialic acids.