THE ENZYMIC INTERCONVERSION OF URIDINE DIPHOSPHOGALACTOSE AND URIDINE DIPHOSPHOGLUCOSE

The enzymic interconversion of uridine diphosphogalactose and uridine diphosphoglucose.

The reversible transformation of galactose into glucose in biological systems is important both for the utilization of dietary galactose as fuel (via hexose 6-phosphate) and for the biosynthesis of complex galactose-containing compounds from glucose or acetate. The first step in the metabolism of galactose in both yeast and animal tissues is phosphorylation in the 1 position of the hexose to fo...

Uridine diphosphoglucose pyrophosphorylase of pea seeds.

and the concentration and type of acceptor amine has been studied. 4. The manometric method has been used to demonstrate that heteropyrithiamine, quinilinothiamine and possibly oxythiamine are thiaminase substrates. 5. The effect of several structural analogues of thiamine on bracken thiaminase has been studied and it is shown that 3-(o-aminobenzyl)-4-methylthiazolium chloride is a powerful but...

Uridine diphosphoglucose dehydrogenase of pea seedlings.

Stability in vitro of uridine diphosphoglucose pyrophosphorylase in Dictyostelium discoideum.

The stability of uridine diphosphoglucose pyrophosphorylase was examined in extracts prepared at different stages of development in Dictyostelium discoideum. In the early stages, the kinetics of inactivation were nonlinear, and, therefore, it was not possible to determine the specific enzyme activity. In the later stages of development, the enzyme was stable, but it could be rapidly inactivated...

Modulation of 5-fluorouracil in mice using uridine diphosphoglucose.

Uridine diphosphoglucose (UDPG) is a precursor of uridine that can be used as a rescuing agent from 5-fluorouracil (5FU) toxicity. Four doses of UDPG (2000 mg/kg i.p. or p.o. at 2, 6, 24, and 30 h after 5FU bolus) allowed the escalation of a weekly bolus of 5FU from 100 mg/kg (5FU100) to 150 mg/kg (5FU150) in healthy and tumor-bearing BALB/c, C57/BI, and CD8F1 (BALB/c x DBA/8) mice. 5FU150 with...