Isolation and somatomedin activity of bovine growth hormone fragment 87-124.
Various bovine growth hormone (GH) fragments were prepared and tested for somatomedin-like activity in vitro. Cyanogen bromide cleavage followed by reduction and alkylation yielded three fragments which were identified as GH (6-124), GH (150-179) and GH (125-149). No consistent effect was found when these preparations were tested for their ability to stimulate in vitro sulfate and thymidine uptake by rat costal cartilage and to compete with [125I]iodoinsulin for insulin-binding sites on placenta membranes. A fourth peptide was isolated by cleavage of the tryptophanyl and methionly bonds of bovine Gh using anhydrous heptofluorobutyric acid and cyanogen bromide. In addition to significant amounts of non-specific cleavage products, a peptide have a molecular weight of about 4800 was isolated. The amino terminal residue was leucine and the carboxyl terminal was homoserine. These data, in addition to the amino acid composition, suggested that the peptide corresponded to residues 87-124. Fragment GH (87-124) stimulated sulfate (minimum effective concentration, 5 . 10-8 M) and thymidine (minimum effective concentration, 10-8M) uptake by rat costal cartilage. It also cross-reacted, albeit weakly, with insulin-binding sites on placenta membrane. Maximum displacement was 35% of non-specific binding. These observations demonstrate that somatomedin-like activity can be generated from the growth hormone molecule which is inherently devoid of such activity.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002356:Cartilage / Q000378:metabolism; D002417:Cattle; D002850:Chromatography, Gel; D003488:Cyanogen Bromide; D004247:DNA / Q000378:metabolism; D005260:Female; D013006:Growth Hormone / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism; D006801:Humans; D008297:Male; D008970:Molecular Weight; D010446:Peptide Fragments / Q000302:isolation & purification* / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D011972:Receptor, Insulin / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D013002:Somatomedins / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism
D000596:Amino Acids; D010446:Peptide Fragments; D013002:Somatomedins; D013431:Sulfates; C012036:sodium sulfate; C031869:somatotropin fragment 87-124; D013006:Growth Hormone; D004247:DNA; D012964:Sodium; D011972:Receptor, Insulin; D003488:Cyanogen Bromide