Purification and point-mutation analysis of human interleukin-2 (Ser-125)

A new type of IL-2(Ser-125) was purified by semi-preparative RP-HPLC, and its purity was analyzed with microbore HPLC, IEF, SDS-PAGE and capillary electrophoresis (CE). The N-terminal sequencing indicated the microheterogeneity of the N-terminus, i.e., N-Met(2/3) and N-Ala(1/3), which was identified with the results of CE and IEF. The amino acid sequence of the point mutated peptide confirmed the replacement of Cys-125 with Ser.