A mutant of human insulin-like growth factor II (IGF II) with the processing sites of proinsulin. Expression and binding studies of processed IGF II

Eur J Biochem. 1992 Dec 15;210(3):665-9. doi: 10.1111/j.1432-1033.1992.tb17467.x.


A mutant of human insulin-like growth factor II (IGF II) was constructed by site-directed mutagenesis: the nucleotides coding for Ser33 and Ser39 were changed to yield Arg and Lys, respectively, thus creating two pairs of basic residues, Arg-Arg and Lys-Arg, as flanking sequences of the remaining C domain. [Arg33, Lys39]IGF II was expressed in NIH-3T3 cells as a processed two-chain peptide with a deletion of amino acid residues 37-40 and crosslinked by three disulfide bonds. This des(37-40)[Arg33]IGF II showed 3.6-fold and 7.4-fold reduced affinities to the type 1 and type 2 IGF receptor overexpressing cells, respectively, whereas the thymidine incorporation potency was the same as that of wild-type IGF II. We speculate that the discrepancy between the reduced binding to the type 1 IGF receptor and the full thymidine incorporation potency is due to the 6.1-fold reduced affinity of the expressed mutant to the co-expressed IGF binding protein 3 (IGFBP-3). The results suggest that des(37-40)[Arg33]IGF II assumes a conformation very similar to IGF II, and that the entire length of the C domain is not essential for biological activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Amino Acid Sequence
  • Animals
  • Carrier Proteins / metabolism
  • Chromatography, High Pressure Liquid
  • Humans
  • Insulin-Like Growth Factor Binding Protein 2
  • Insulin-Like Growth Factor II / genetics*
  • Insulin-Like Growth Factor II / isolation & purification
  • Insulin-Like Growth Factor II / metabolism
  • Kinetics
  • Mice
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed*
  • Oligodeoxyribonucleotides
  • Proinsulin / genetics*
  • Receptor, IGF Type 1 / metabolism
  • Receptor, IGF Type 2 / metabolism
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Restriction Mapping
  • Transfection


  • Carrier Proteins
  • Insulin-Like Growth Factor Binding Protein 2
  • Oligodeoxyribonucleotides
  • Receptor, IGF Type 2
  • Recombinant Proteins
  • Insulin-Like Growth Factor II
  • Proinsulin
  • Receptor, IGF Type 1