UDP-N-acetylglucosamine 4-epimerase activity
Definition
Target type: molecularfunction
Catalysis of the reaction: UDP-N-acetyl-D-glucosamine = UDP-N-acetyl-D-galactosamine. [EC:5.1.3.7]
UDP-N-acetylglucosamine 4-epimerase activity catalyzes the reversible interconversion of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylmannosamine (UDP-ManNAc). This enzymatic activity is critical for the biosynthesis of various essential biomolecules, including N-glycans, glycosaminoglycans, and bacterial cell wall components.
The reaction mechanism involves the stereochemical inversion at carbon 4 of the hexose ring, transforming the hydroxyl group at the C4 position of UDP-GlcNAc to an amino group in UDP-ManNAc. This transformation requires the enzyme to utilize a transient covalent intermediate, likely a Schiff base formed between the substrate and a lysine residue in the active site.
The precise molecular mechanism is complex and involves a series of steps including substrate binding, proton abstraction, hydride transfer, and product release. The epimerase activity is influenced by a number of factors, including the presence of metal ions like manganese, the pH of the reaction environment, and the concentration of substrates.
In summary, UDP-N-acetylglucosamine 4-epimerase activity plays a crucial role in sugar metabolism by catalyzing the conversion of UDP-GlcNAc to UDP-ManNAc, an essential precursor for the synthesis of a wide range of complex carbohydrates. The molecular mechanism involves a complex series of steps, including the formation of a covalent intermediate and a stereochemical inversion at the C4 position of the hexose ring.'
"
Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| UDP-glucose 4-epimerase | A UDP-glucose 4-epimerase that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q14376] | Homo sapiens (human) |
Compounds (5)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| ebselen | ebselen : A benzoselenazole that is 1,2-benzoselenazol-3-one carrying an additional phenyl substituent at position 2. Acts as a mimic of glutathione peroxidase. | benzoselenazole | anti-inflammatory drug; antibacterial agent; anticoronaviral agent; antifungal agent; antineoplastic agent; antioxidant; apoptosis inducer; EC 1.13.11.33 (arachidonate 15-lipoxygenase) inhibitor; EC 1.13.11.34 (arachidonate 5-lipoxygenase) inhibitor; EC 1.3.1.8 [acyl-CoA dehydrogenase (NADP(+))] inhibitor; EC 1.8.1.12 (trypanothione-disulfide reductase) inhibitor; EC 2.5.1.7 (UDP-N-acetylglucosamine 1-carboxyvinyltransferase) inhibitor; EC 2.7.10.1 (receptor protein-tyrosine kinase) inhibitor; EC 3.1.3.25 (inositol-phosphate phosphatase) inhibitor; EC 3.4.22.69 (SARS coronavirus main proteinase) inhibitor; EC 3.5.4.1 (cytosine deaminase) inhibitor; EC 5.1.3.2 (UDP-glucose 4-epimerase) inhibitor; enzyme mimic; ferroptosis inhibitor; genotoxin; hepatoprotective agent; neuroprotective agent; radical scavenger |
| ethacrynic acid | etacrynic acid : An aromatic ether that is phenoxyacetic acid in which the phenyl ring is substituted by chlorines at positions 2 and 3, and by a 2-methylidenebutanoyl group at position 4. It is a loop diuretic used to treat high blood pressure resulting from diseases such as congestive heart failure, liver failure, and kidney failure. It is also a glutathione S-transferase (EC 2.5.1.18) inhibitor. Ethacrynic Acid: A compound that inhibits symport of sodium, potassium, and chloride primarily in the ascending limb of Henle, but also in the proximal and distal tubules. This pharmacological action results in excretion of these ions, increased urinary output, and reduction in extracellular fluid. This compound has been classified as a loop or high ceiling diuretic. | aromatic ether; aromatic ketone; dichlorobenzene; monocarboxylic acid | EC 2.5.1.18 (glutathione transferase) inhibitor; ion transport inhibitor; loop diuretic |
| haloprogin | haloprogin: minor descriptor (73-86); on-line & INDEX MEDICUS search PHENYL ETHERS (73-86) | aromatic ether | |
| diethylstilbestrol | diethylstilbestrol : An olefinic compound that is trans-hex-3-ene in which the hydrogens at positions 3 and 4 have been replaced by p-hydroxyphenyl groups. Diethylstilbestrol: A synthetic nonsteroidal estrogen used in the treatment of menopausal and postmenopausal disorders. It was also used formerly as a growth promoter in animals. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), diethylstilbestrol has been listed as a known carcinogen. (Merck, 11th ed) | olefinic compound; polyphenol | antifungal agent; antineoplastic agent; autophagy inducer; calcium channel blocker; carcinogenic agent; EC 1.1.1.146 (11beta-hydroxysteroid dehydrogenase) inhibitor; EC 3.6.3.10 (H(+)/K(+)-exchanging ATPase) inhibitor; endocrine disruptor; xenoestrogen |
| psammaplin a | psammaplin A: isolated from marine sponges Poecillastra and Jaspis; structure in second source |