**Background**
Protein synthesis is a fundamental biological process essential for cell growth, proliferation, and the maintenance of cellular homeostasis. The translation of mRNA into polypeptide chains by ribosomes is a tightly regulated mechanism, and any disruption in this process can lead to significant cellular stress or cell death. Understanding the dynamics of translation is critical for researching various pathologies, including viral infections and malignancy. In the context of oncology, studying the rate of protein synthesis helps in identifying vulnerabilities in rapidly dividing cells. Therefore, we will introduce an aminoglycoside antibiotic used to study translation and induce cytotoxicity – Puromycin.
**Definition**
Puromycin is an aminoglycoside antibiotic that acts as a protein synthesis inhibitor. According to the Puromycin description, it is provided as a dihydrochloride salt and functions as an analog of the 3′ end of aminoacyl-tRNA.
**Mechanism of Action**
Puromycin inhibits protein synthesis through two primary modes of action. First, it acts as an acceptor substrate that attacks peptidyl-tRNA in the P site of the ribosome to form a nascent peptide. Second, it competes with aminoacyl-tRNA for binding to the A site. This leads to the premature termination of translation and the release of incomplete peptide chains, resulting in the accumulation of small peptides. Because of this unique Puromycin biological activity, the incorporation of the drug into newly synthesized proteins can be used to directly reflect the rate of mRNA translation. Furthermore, puromycin immunodetection serves as a non-radioactive alternative to amino acid labeling, allowing for the evaluation of translation activity in single cells via immunofluorescence microscopy or in heterogeneous populations using fluorescence-activated cell sorting.
**In Vitro Studies**
The cytotoxic effects of puromycin have been extensively documented across various human cell lines. In vitro studies demonstrate that puromycin exhibits potent growth inhibition and cytotoxicity. In HEK293 cells, the IC50 values vary depending on the assay and duration, ranging from 0.35 nM (alamar blue assay) to 0.81 μM (resazurin assay after 72 h). Specifically, puromycin showed an IC50 of 0.36 μM in HEK293 cells after 72 h using PrestoBlue staining. In human A549 cells, the IC50 was reported at 0.6 μM, while in BEAS-2B cells with low TrxR expression, the IC50 was 0.74 μM after 48 h of incubation. Additionally, puromycin exhibited an EC50 of 6.1 μM in HCT-8 cells and a CC50 of 0.42 μM in HEK-293T cells after 72 h. In HL-60 cells, antiproliferative activity was observed with an EC50 of 0.055 μM after 72 h. In conclusion, puromycin is a powerful inhibitor of protein synthesis that serves as a critical tool for studying translation and cellular cytotoxicity.
Keywords
Puromycin, 53-79-2, CL13900, CL 13900, CL-13900, Bacterial, Antibiotic, Parasite, Inhibitor, inhibitor, inhibit
References
[1] Nathans D, et al. Puromycin inhibition of protein synthesis: incorporation of puromycin intopeptide chains. Proc Natl Acad Sci U S A. 1964 Apr;51:585-92.
[2] Miyamoto-Sato E, et al. Specific bonding of puromycin to full-length protein at the C-terminus. Nucleic Acids Res. 2000 Mar 1;28(5):1176-82.
[3] Schmidt EK, et al. SUnSET, a nonradioactive method to monitor protein synthesis. Nat Methods. 2009 Apr;6(4):275-7.