PYR-41 is a cell permeable, irreversible inhibitor of ubiquitin activating enzyme E1 with little or no activity against E2s or E3s (IC50 < 10 μM). It blocks degradation of p53 and inhibits NF-kappaB-dependent pathways. PYR-41 also increases SUMOylation of proteins.

4–[4–[(5–Nitro–2–furanyl)methylene]?–3,5–dioxo–1–pyrazolidinyl]benzoic acid ethyl ester

>98% by TLC.

Soluble in DMSO (100 mM)

Brown powder

Store at +4°C. Stable as supplied for up to 2 years when stored dessicated at +4°C. Store solutions at -20°C for up to 1 week.

Useful for inhibition of E1 ubiquitin conjugating enzymes

1. Yang et al (2007). Inhibitors of ubiquitin-activating enzyme (E1), a new class of potential cancer therapeutics. Cancer Res. 67:9472.
2. Mi et al (2009). Cancer preventative isothiocyanates induce selective degradation of cellular ?- and ?-tubulins by proteasomes. J. Biol. Chem. 284:17039.
3. Brahemi et al (2010). Homology modelling of human E1 ubiquitin activating enzyme. Lett. Drug Des. Discov. 7:57.

Protect from light. Protect from moisture. Avoid freeze/thaw cycles.

Ubiquitin Enzymes

Inhibitors/Activators