Interleukin 1 receptor antagonist (IL1RN), also known as IL1-RA, is a member of the interleukin 1 cytokine family. IL1RN may represent a reservoir of IL-1 inhibitors, released upon cell death, whose function is no limit the pro-inflammatory signals but most prominently by mononuclear phagocytes and keratinocytes. IL1RN is reported to be associated with increased risk of osteoporotic fractures and gastric cancer. Source: Recombinant protein corresponding to aa27-178 of mouse IL-1ra/IL-1F3, fused to His-tag at N-terminal expressed in E. coli. Molecular Weight: ~20kD (177aa), confirmed by MALDI-TOF Endotoxin: <1EU/1ug (determined by LAL method) Biological Activity: Measured by its ability to inhibit proliferation using D10.G4.1 mouse helper T cells. The ED50 for this effect is less or equal to 60 ng/ml with Mouse IL-1 alpha. Amino Acid Sequence: MGSSHHHHHH SSGLVPRGSH MGSHMRPSGK RPCKMQAFRI WDTNQKTFYL RNNQLIAGYL QGPNIKLEEK IDMVPIDLHS VFLGIHGGKL CLSCAKSGDD IKLQLEEVNI TDLSKNKEED KRFTFIRSEK GPTTSFESAA CPGWFLCTTL EADRPVSLTN TPEEPLIVTK FYFQEDQ Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 6 months after receipt at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.