Insulin and IGF binding by IGFBP-3 fragments derived from proteolysis, baculovirus expression and normal human urine

Peter Vorwerk, Yoshitaka Yamanaka, Anna Spagnoli, Youngman Oh, Ron G. Rosenfeld

Research output: Contribution to journalArticle

46 Scopus citations


Recombinant human IGFBP-3 was proteolysed with different concentrations of plasmin for various periods of time. The major IGFBP-3 fragment resulting from this digestion migrated at ca. 15 kDa in nonreducing SDS-PAGE. Following the identification of this fragment as an N-terminal IGFBP-3 fragment, by use of N-terminus-specific monoclonal antibody and amino acid sequence analysis, we constructed and expressed a similar fragment in a baculovims expression system. The fragments resulting from plasmin digestion, as well as the baculovirus-expressed recombinant human IGFBP-31-97, retain weak IGF binding and show specific insulin binding on cross-linking and western ligand blot. RhIGFBP-31-97 can inhibit insulin receptor autophosphorylation in insulin receptor-overexpressing NIH 3T3 cells. Insulin and IGF binding to IGFBP-3 fragments could be further demonstrated in normal urine. These data indicate the physiological significance of IGFBP-3 fragments derived from proteolysis in vivo.

Original languageEnglish (US)
Pages (from-to)1392-1395
Number of pages4
JournalJournal of Clinical Endocrinology and Metabolism
Issue number4
StatePublished - Jan 1 1998


ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

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