EXPRESSION OF A RECOMBINANT HUMAN GROWTH-HORMONE BINDING-PROTEIN IN BACULOVIRUS INSECT CELL SYSTEM/

An eucaryotic recombinant human growth hormone binding protein (rGHBP) was expressed in baculovirus-infected insect cells and purified by af finity chromatography from culture supernatant. This mannose-rich 34-k Da protein specifically bound human growth hormone (hGH) with the same affinity (kDa = 0.42 x 10(-9) M) than the 51.5 kDa GHBP we purified a nd characterised from human plasma (kDa = 1.1 x 10(-9) M). A high mole cular form of the rGHBP was detected by silver-stained SDS-PAGE, Weste rn blot (mAb 263), affinity cross-linking and Western ligand blot with I-125-hGH. Reduction experiments with beta-mercaptoethanol suggested that this form involved a disulfide bound between two rGHBPs.