Open AccessDisulfide arrangement of human insulin‐like growth factor I derived from yeast and plasma
Author(s) -
AXELSSON Kent,
JOHANSSON Stig,
EKETORP Gunilla,
ZAZZI Henric,
HEMMENDORF Barbro,
GELLERFORS Pär
Publication year - 1992
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1992.tb17010.x
Subject(s) - yeast , human plasma , disulfide bond , growth factor , insulin like growth factor , insulin , chemistry , endocrinology , biochemistry , medicine , biology , chromatography , receptor
The disulfide arrangement of yeast derived human insulin‐like growth factor I (yIGF‐I) was determined using a combination of Staphylococcus aureus V8 protease mapping, fast‐atom‐bombardment mass spectrometry as well as amino acid sequence and composition analysis. Three disulfide bridges were found between the following cysteine residues: Cys6‐Cys48, Cys47‐Cys52 and Cys18‐Cys61. IGF‐I isolated from human plasma (pIGF‐I) was found to have an identical dilsufide configuration. A yeast‐derived isomeric form of IGF‐I (yisoIGF‐I) exhibited an altered disulfide arrangement: Cys6‐Cys47, Cys48‐Cys52 and Cys18‐Cys61. Radioreceptor analysis of pIGF‐I and yIGF‐I showed high specific activity, 20 000 U/mg. However, yisoIGF‐I demonstrated a severely reduced ability to bind to the IGF‐I receptor (19%) and was less potent in provoking a mitogenic response in Balb/C 3T3 fibroblasts (50% at doses 10–100 ng/ml). The data demonstrate the importance of correct disulfide arrangement in IGF‐I for full biological activity.