Tunicamycin

Chemical structure: nucleoside

Contains homologues A,B,C, and D. Composition may vary from lot to lot. Actual content given on label.

Tunicamycin is an antibiotic and a glycosylation inhibitor. Its mode of action includes blocking human UDP-HexNAc:polyprenol-P HexNAc-1-P enzymes in the enzyme GlcNAc phosphotransferase (GPT). Glycosylation is a major post-translational modification that plays a critical role in glycoprotein folding, stability, and subcellular localization, as well as in the biological functions of the glycoprotein. Abnormal glycosylation has been identified as a signature of cancer and has been shown to play a significant role in tumor progression, metastasis, and chemoresistance. Research shows tunicamycin exhibits antitumor action. Furthermore, tunicamycin inhibition of N-glycosylation ultimately results in the build-up of unstructured proteins in the endoplasmic reticulum (ER) lumen, potentially leading to ER stress. Tunicamycin also exhibits antibacterial and antifungal actions. It blocks the formation of protein N-glycosidic linkages by inhibiting the transfer of N-acetylglucosamine 1-phosphate to dolichol monophosphate. Tunicamycin also Inhibits bacterial and eukaryote N-acetylglucosamine transferases and prevents the formation of N-acetylglucosamine lipid intermediates.

Tunicamycin has been used to study the effect of N-linked glycosylation of human proton-coupled folate transporter (HsPCFT) in HeLa cells. Tunicamycin has also been used to study the functional effects of coxsackievirus and adenovirus receptor (CAR) glycosylation in COS-7 cells. Tunicamycin from Streptomyces sp. has been used to inhibit N-glycosylation in cell culture experiments.

Blocks the formation of protein N-glycosidic linkages.

Tunicamycin dissolves in DMSO at 4.9-5.1 mg/ml and yields a clear to very slightly hazy, colorless to yellow solution. Furthermore, tunicamycin is soluble in DMF (>10 mg/ml), pyridine (>10 mg/ml), water (<5 mg/ml, pH 9.0), dioxane (<1 mg/ml) and THF. However, it is insoluble in other organic solvents such as acetone, chloroform, and ethyl acetate, and in aqueous solutions with pH <6. Aqueous solutions can be prepared from stock solutions by diluting with water at pH 8-10 or with buffers with pH >7, preferably >8. Tunicamycin will not dissolve in phosphate buffer, pH 8, at 1 mg/ml, even with heating, but solubility can be achieved by raising the pH to 9 and back titrating to pH 7-8.