| 内容提要: |
Interleukin-2 (IL-2) was identified in 1976 as a T-cell growth factor (TCGF) activity in the supernatants of activated T cells. In 1979, TCGF was assigned interleukin 2 (IL-2) at the Second International Lymphokine Workshop.IL-2 is a 15.5KD type I cytokine consisting of 153 amino acids (aa), including a 20 amino acids signal peptide. PI is 6.5 - 8.0 . Mature IL-2 is a hydrophobic protein that is a bundle of four overlapping alpha-helices formed by a typical up-up-down-down topology of 133 amino acids. IL-2 have three cysteines located at 58,105 and 125 respectively, C58 and C105 form a disulfide bond that plays a key role for IL-2 activity. SO recombinant IL-2 usually changes the 125-position free cysteine residue to either serine or alanine, which facilitates the recombinant protein to produce the correct disulfide bond. The activity of IL-2 was stable to heat, at 56 ℃ for 1h, 37 ℃ for 12h or 70 ℃ for 15min, and remained stable at 4 ℃ for more than 1 year. IL-2 is proteolytic and insensitive to DNase, RNase and neuraminidase. |