title: Recombinant goldfish growth hormones (gfGH-I and -II) expressed in Escherichia coli have similar biological activities.
abstract: Complementary DNA regions coding for two different mature goldfish growth hormones (gfGH-I and gfGH-II) with four and five cysteine residues were cloned into the bacterial expression vector, pRSETA. The recombinant gfGH-I (five cysteines) and -II (four cysteines) were produced in Escherichia coli as the fusion proteins carrying N-terminal 6XHis tag, which facilitates purification by using metal chelating affinity chromatography under denaturing condition with urea. The recombinant hormones were further refolded by gradually removing the urea. Native gfGH was also purified from goldfish pituitary glands and served as a positive control in the present study. The native and recombinant hormones were tested in goldfish hepatic radioreceptor assay and in vitro Spi 2.1 promoter activation assay. Our results showed that the two recombinant gfGHs are biologically active, and they have similar biological activities despite their having different cysteine contents.
authors.affiliation: Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong Special Administrative Region, PR China.
authors.forename: Yuk Hang
authors.initials: YH
authors.lastname: Chan
authors.forename: Christopher H K
authors.initials: CH
authors.lastname: Cheng
authors.forename: King Ming
authors.initials: KM
authors.lastname: Chan
mesh_terms: D000818:Animals; D004926:Escherichia coli / Q000378:metabolism*; D006054:Goldfish / Q000378:metabolism*; D013006:Growth Hormone / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D008099:Liver / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics; D010902:Pituitary Gland / Q000737:chemistry; D011401:Promoter Regions, Genetic / Q000502:physiology; D017510:Protein Folding; D020033:Protein Isoforms / Q000378:metabolism / Q000502:physiology; D011869:Radioligand Assay; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D009687:Nuclear Proteins; D020033:Protein Isoforms; D011994:Recombinant Proteins; D013006:Growth Hormone