[Expression of grass carp growth hormone in the yeast Pichia pastoris]

Growth hormone plays an essential role in the stimulation of somatic growth and development. To produce large amount of grass carp growth hormone (gcGH) of biological activity for further use, this study aimed at high-yield expression of gcGH in the yeast Pichia pastoris. The gcGH cDNA was inserted into a yeast vector, pGAPZ-alpha-B. Under the control of the promoter GAP (glyceraldehyde 3-phosphate dehydrogenase), a 22-kilodalton protein, similar to the molecular weight of native growth hormone, was detected in the supernatant of transformed yeast. It led to a level as high as of 50 mg/L. This protein could be specifically immunoprecipitated with rabbit polyclonal antibodies raised against gcGH. A receptor ELISA Sandwich method was also performed to verify the biological activity of the in vitro expressed gcGH.