Direct identification of disulfide bond linkages in human insulin-like growth factor I (IGF-I) by chemical synthesis.
The primary structure of human IGF-I, except for the disulfide bond system, has been reported by Rinderknecht and Humbel. IGF-I afforded the corresponding characteristic peptide fragment on V8 protease digestion, which contained Cys6, Cys47, Cys48, and Cys52. Two possible fragments, Type I with Cys6-Cys47 and Cys48-Cys52, and Type II with Cys6-Cys48 and Cys47-Cys52, were synthesized. The disulfide bond system of IGF-I was unequivocally determined to be the Type II form along with Cys18-Cys61. Interestingly, the Type I system was included in the disulfide bond isomer produced as the main by-product in the refolding step on IGF-I synthesis by the recombinant DNA method.
Iwai
M
M
Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., Osaka.
Kobayashi
M
M
Tamura
K
K
Ishii
Y
Y
Yamada
H
H
Niwa
M
M
D003545:Cysteine; D004220:Disulfides / Q000138:chemical synthesis; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000138:chemical synthesis*; D015394:Molecular Structure; D010446:Peptide Fragments / Q000138:chemical synthesis; D011994:Recombinant Proteins / Q000096:biosynthesis; D013002:Somatomedins / Q000138:chemical synthesis*
D004220:Disulfides; D010446:Peptide Fragments; D011994:Recombinant Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D003545:Cysteine