Synthesis of UDP-4-deoxy-4-fluoroglucose and UDP-4-deoxy-4-fluorogalactose and their interactions with enzymes of nucleotide sugar metabolism

Article abstract of DOI:10.1021/jo00102a024

Fluorinated carbohydrates can be used as probes of enzymatic active sites. We report the synthesis of 4-deoxy-4-fluoro-α-D-galactose-1-phosphate and the substrate analogues of UDP-galactose, UDP4-deoxy-4-fluoro-α-D-galactose (UDP-FGal), and of UDP-glucose, UDP-4-deoxy-4-fluoro-α-D-glucose (UDP-FGlc), which may be useful in analyzing the binding properties of enzymes that utilize nucleotide sugars as substrates. As a first step in this study, we determine the kinetic and inhibition parameters for UDP-FGal and UDP-FGlc interacting with UDP-glucose dehydrogenase and UDP-galactose 4-epimerase. UDP-FGlc is a substrate for bovine liver UDP-glucose dehydrogenase: K(m) = 30.2 ± 4.5 μM slightly higher than the value 9.6 ± 0.7 μM for UDP-glucose, and V(m)(UDP-FGlc) = 0.46V(mUDP-Glc). UDP-FGal is not a substrate for UDP-glucose dehydrogenase but is a competitive inhibitor with respect to UDP-glucose (K(i) = 19.9 ± 6.6 μM). These analogs also bind to UDP-galactose 4-epimerase from E. coli with dissociation constants K(d) of 1.4 and 1.1 mM for UDP-FGlc and UDP-FGal, respectively.