Structure–Activity Studies of Glucose Transfer: Determination of the Spontaneous Rates of Hydrolysis of Uridine 5′-Diphospho-α-d-glucose (UDPG) and Uridine 5′-diphospho-α-d-glucuronic acid (UDPGA)

Kinetic and NMR spectroscopic study of the chemical stability and reaction pathways of sugar nucleotides

“…The results obtained with glucose-1-UDP (1) are fully consistent with those obtained in kinetic [14,15] and NMR studies [17] previously. In addition to the clear results obtained by 31 P NMR, the results show that the progress of the reaction resulting in a formation of two monophosphates 3 and 4 can be seen also by 1 H NMR, as the H6 signals of 1 and 4 can be seen separately.…”

“…Only under acidic conditions, the reaction takes place at the anomeric carbon. [14,18] The reaction is similar to that of the acid-catalysed hydrolysis of other glycosides: A nucleoside diphosphate is released as a leaving group and an oxocarbenium intermediate is formed. [18] Biological processes of reducing sugar nucleotides utilise the carbonyl group of the acyclic form as a means to attach a monomeric or polymeric ADP-ribosyl structure to a protein.…”

“…In the present work, the alkaline cleavage of glucose 1-UDP (1) and ribose 5-UDP (6) were followed by 1 H and 31 P NMR experiments to obtain information on the processes taking place in the non-chromophoric sugar moiety. Nunez and Barker, [13] as well as Bedford et al [14] have previously proved the formation of 3 in the presence of metal catalysts by experiments with authentic samples. More recently, the formation of 3 in the presence of Mg 2þ ions under neutral and slightly alkaline conditions has been shown by 31 P NMR experiments.…”

“…[1,2,5] In chemical reactions, an intramolecular nucleophilic attack occurs under neutral and alkaline conditions. [13][14][15][16][17] A neighbouring HO-group in cis-orientation attacks on the a-phosphate (in this context a refers to the sugar bound phosphate in the pyrophosphate moiety) (Scheme 1). The reaction of 1 results in the formation of glycopyranose 1,2-cyclic monophosphate (3) and uridine 5 0 -monophosphate (5 0 -UMP, 4).…”

Glucuronidation of Polychlorinated Biphenylols and UDP-Glucuronic Acid Concentrations in Channel Catfish Liver and Intestine

“…The values for trout and carp (Zhivkov et al, 1975) were determined from liver homogenized in perchloric acid to solubilize the nucleotides. This process may have led to hydrolysis of UDPGA to UDP and glucuronic acid, which has been shown to increase with decreased pH (Bedford et al, 2003).…”