Recombinant Human IL-15 produced in E.Coli is a single, non-glycosylated, polypeptide chain containing 114 amino acids and having a molecular mass of 13007 Dalton. rHuIL-15 is purified by proprietary chromatographic techniques
Sterile Filtered White lyophilized (freeze-dried) powder.
Formulation & Packaging
The protein was lyophilized from a concentrated (1mg/ml) solution with 5mM Tris pH 8.0.
The lyophilized rHuIL-15 is very soluble in water and most aqueous buffers below and above the isoelectric point (pI=5.7).
Lyophilized rHuIL-15 although stable at room temperature, should be stored desiccated below 0°C. Reconstituted rHuIL-15 is best stored refrigerated at 4°C.
Greater than 99.0% as determined by:
Analysis by RP-HPLC
Analysis by reducing and non-reducing SDS-PAGE Silver Stained
(Limit of acceptance:?98.0%. No more than 2% total impurities; no single impurity greater than 1%)
Amino Acid Composition
In total agreement with the expected amino acid composition of native Human IL-15.
Amino acid sequence
The sequence of the first five N-terminal amino acids was determined and was found to be Met-Asn-Trp-Val-Asn, which agrees with the sequence of native Human IL-15.
Dimers and aggregates
Less than 1% as determined by silver-stained SDS-PAGE gel analysis.
ProSpec's rHuIL-15 is fully biologically active when compared to standard. The ED50 as determined by the dose-dependant stimulation of the proliferation of CTLL-2 was found to be < 0.45 ng/ml, corresponding to a Specific Activity of 3 x 106 IU/mg.
Less than 0.1 ng/µg (IEU/µg) of rHuIL-15.
Protein quantitation was carried out by two independent methods:
UV spectroscopy at 280 nm using the absorbency value of 0.55 as the extinction coefficient for a 0.1% (1mg/ml) solution. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics)