The C-branched sugar d-apiose (Api) is essential for plant cell-wall development. An enzyme-catalyzed decarboxylation/pyranoside ring-contraction reaction leads from UDP-α-d-glucuronic acid (UDP-GlcA) to the Api precursor UDP-α-d-apiose (UDP-Api). We examined the mechanism of UDP-Api/UDP-α-d-xylose synthase (UAXS) with site-selectively 2 H-labeled and deoxygenated substrates. The analogue UDP-2...

UDP-glucose dehydrogenase catalyses the conversion of UDP-glucose into UDP-GlcA, a critical precursor for glycan synthesis across evolution. We have cloned the gene encoding this important enzyme from the opportunistic pathogen Cryptococcus neoformans. In this fungus, UDP-GlcA is required for the synthesis of capsule polysaccharides, which in turn are essential for virulence. The gene was expre...

It has been previously demonstrated (1) that particulate preparations from Phase&s uureus (mung bean) seedlings are capable of catalyzing the formation of uridine diphosphate-ngalacturonic acid1 and a mixture of UDP-n-xylose and UDP-Larabinose from UDP-n-glucuronic acid. The results indicated that the preparations contained UDP-uranic acid 4-epimerase and UDP-uranic acid decarboxylase activitie...

UDP-glucuronosyltransferases (EC 2.4.1.17) is an isoenzyme family located primarily in the hepatic endoplasmic reticulum (ER) that displays latency of activity both in vitro and in vivo, as assessed respectively in microsomes and in isolated liver. The postulated luminal location of the active site of UDP-glucuronosyltransferases (UGTs) creates a permeability barrier to aglycone and UDP-GlcA ac...

Identification of a G protein-coupled receptor activated by UDP-glucose led us to develop a sensitive and specific assay for UDP-glucose mass and to test whether this sugar nucleotide is released as an extracellular signaling molecule. Mechanical stimulation of 1321N1 human astrocytoma cells by a change of medium resulted in an increase in extracellular levels of both ATP and UDP-glucose. Where...

UDP-N-acetyl-L-fucosamine is a precursor to l-fucosamine in the lipopolysaccharide of Pseudomonas aeruginosa serotype O11 and the capsule of Staphylococcus aureus type 5. We have demonstrated previously the involvement of three enzymes, WbjB, WbjC, and WbjD, in the biosynthesis of UDP-2-acetamido-2,6-dideoxy-L-galactose or UDP-N-acetyl-L-fucosamine (UDP-l-FucNAc). An intermediate compound from ...

Tritiated uridine-5'-diphosphogalactose (UDP-[3H]Gal) has been widely used to study oligosaccharide biosynthesis and structure. It can be synthesized either chemically or enzymatically using galactose oxidase to oxidize the hydroxyl moiety at C-6 to an aldehyde (6-aldo-UDP-Gal), which is then reduced back to the alcohol with tritiated sodium borohydride. Although the enzymatic approach is simpl...

We have identified an operon and characterized the functions of two genes from the severe food poisoning bacterium, Bacillus cereus subsp. cytotoxis NVH 391-98 that are involved in the synthesis of a unique UDPsugar, UDP-2-Acetamido-2-deoxy-xylose (UDPN-acetyl-xylosamine, UDP-XylNAc). UGlcNAcDH encodes a UDP-N-acetylglucosamine 6-dehydrogenase converting UDPN-acetyl-glucosamine (UDP-GlcNAc) to ...

The interactions of Mn2+, nucleotides, monosaccharide substrates, and the modifier protein alpha-lactalbumin with galactosyltransferase have been studied by difference spectroscopy. MnCl2, required for significant binding of UDP-galactose or UDP to the enzyme, does not exhibit specific interactions with tyrosine or tryptophan residues. The interaction of UDP-galactose or UDP with galactosyltran...

The pool levels of the nucleotide precursors of peptidoglycan were analyzed after inhibition of protein synthesis in various Escherichia coli strains. In all cases UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylmuramyl-pentapeptide (UDP-MurNAc-pentapeptide) cell pools increased upon treatment with chloramphenicol or tetracycline. Similar results were observed after the treatment of K-12 s...