Leptin pegylated antagonist (mutant L39A/D40A/F41A)

Mono-pegylated (with 20 kDa PEG) recombinant human leptin antagonist is one polypeptide chain containing 146 amino, an additional Ala at N-terminus and one molecule of PEG 20 kDa at its N-terminus, having an expected molecular mass of ~ 35.6 kDa as determined by MS. However due to enlarged hydrodymanic volume recombinant human leptin antagonist runs on the SDS-PAGE as 48 kDa protein and in gel-filtration on Superdex 200 as over 200 kDa protein. Human pegylated recombinant leptin antagonist half-life in circulation after SC injection was over 20 hours. Human pegylated recombinant leptin antagonist was initially mutated, resulting in L39A/D40A/F41A mutant that was purified by proprietary chromatographic techniques according to Niv-Spector et al, Biochem. J 291;221-230 (2005) . and its pegylation was similar to that is described in Elinav et al. for mouse leptin antagonist see Endocrinology 150:3083-91 (2009) .