A kinetic study on the chemical cleavage of nucleoside diphosphate sugars.
Nucleoside diphosphate sugars serve in essential roles in metabolic processes. They have, therefore, been used in mechanistic studies on glycosylation reactions, and their analogues have been synthesised as enzyme and receptor inhibitors. Despite extensive biochemical research, little is known about their chemical reactions. In the present work the chemical cleavage of two different types of nucleoside diphosphate sugars has been studied. UDP-Glc is phosphorylated at the anomeric carbon, whereas in ADP-Rib C-1 is unsubstituted, allowing hence the equilibrium between cyclic hemiacetal and acyclic carbonyl forms. Due to the structural difference, these substrates react via different pathways under slightly alkaline conditions: while UDP-Glc reacts exclusively by a nucleophilic attack of a glucose hydroxyl group on the diphosphate moiety, ADP-Rib undergoes a complex reaction sequence that involves isomerisation processes of the acyclic ribose sugar and results in a release of ADP.
Huhta
Eija
E
Department of Chemistry, University of Turku, FIN-20014 Turku, Finland.
Parjanen
Atte
A
Mikkola
Satu
S
D000244:Adenosine Diphosphate / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D009702:Nucleoside Diphosphate Sugars / Q000737:chemistry* / Q000378:metabolism*; D010766:Phosphorylation; D012266:Ribose / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D014530:Uridine Diphosphate / Q000737:chemistry* / Q000378:metabolism; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000737:chemistry* / Q000378:metabolism
D009702:Nucleoside Diphosphate Sugars; D014537:Uridine Diphosphate N-Acetylglucosamine; D014530:Uridine Diphosphate; D000244:Adenosine Diphosphate; D012266:Ribose