The sequence of the first five N-terminal amino acids was determined and was found to be Met-Ala-Pro-Thr-Ser.
The ED50 as determined by the dose-dependant stimulation of murine CTLL-2 cells is < 0.0645 ng/ml, corresponding to a Specific Activity of 15,500,000IU/mg.
The protein (1.1mg/ml) was lyophilized after extensive dialysis against 0.17mg sodium monobasic & 0.89mg dibasic sodium phosphate buffer to a pH=7.5.
Sterile Filtered White lyophilized (freeze-dried) powder.
Protein quantitation was carried out by two independent methods
1. UV spectroscopy at 280 nm using the absorbency value of 0.614 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).
2. Analysis by RP-HPLC, using a calibrated solution of IL-2 as a Reference Standard.
Greater than 98.0% as determined by:
(a) Analysis by RP-HPLC.
(b) Analysis by SDS-PAGE.
It is recommended to reconstitute the lyophilized Interleukin 2 in sterile 20mM AcOH not less than 100ug/ml, which can then be further diluted to other aqueous solutions.
Lyophilized Interleukin-2 although stable at room temperature for 3 weeks, should be stored desiccated below -18oC. Upon reconstitution IL2 should be stored at 4oC between 2-7 days and for future use below -18oC.
For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA).
Please avoid multiple freeze-thaw cycles.
T-cell growth factor (TCGF), Aldesleukin, Lymphokine, IL-2.
