Leptin pegylated super antagonist (mutant D23L/L39A/D40A/F41A)

Mono-pegylated mouse super leptin antagonist (with 20 kDa PEG) 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 pegylated recombinant super mouse leptin antagonist runs on the SDS-PAGE as a 55 kDa protein and in gel-filtration on Superdex 200 as over 200 kDa protein. Pegylated recombinant super mouse leptin antagonist half-life in circulation after SC injection was over 20 hours. Super mouse leptin antagonist (SMLA) was initially mutated, resulting in D23L/L39A/D40A/F41A mutant that was purified by proprietary chromatographic techniques. Its pegylation is similar to that described in Elinav et al. Endocrinology 150:3083-91 (2009) for pegylated recombinant mouse leptin antagonist.