[Purification and activity assay of HSA-AX15 (R13K) fusion protein expressed in Pichia pastoris].

To increase the in vivo half-life of human CNTF mutein AX15 (R13K), HSA-AX15 (R13K) fusion protein was constructed by the fusion of the C-terminus of HSA to the N-terminus of AX15 (R13K) via an 11 amino acids linker. HSA-AX15 (R13K) fusion protein was purified to homogeneity by cation exchange chromatography, reverse phase chromatography and gel filtration after expressed in pichia pastoris. TF-1 cell survival bioassay showed the biological activity of AX15 (R13K) was not affected by the fusion to HSA. It was demonstrated that tertian injection of 4.8 mg/kg HSA-AX15 (R13K) fusion protein could produce more potent anti-obesity effects on KM mice than daily injection of 1.6 mg/kg AX15 (R13K). The long-acting form of hCNTF variant has the potential to reduce discomfort by requiring fewer injections and to minimize the side-effects by decreasing the dosage and fluctuation of plasma concentration, and thus has superior clinical application.