Insulin-Like Growth Factor (IGF) Binding Protein Complementary Deoxyribonucleic Acid from Human HEP G2 Hepatoma Cells: Predicted Protein Sequence Suggests an IGF Binding Domain Different from Those of the IGF-I and IGF-II receptors

Yao Ling Lee, Raymond L. Hintz, Philip M. James, Phillip D.K. Lee, John E. Shively, David R. Powell

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Abstract

The primary structure of an insulin-like growth factor (IGF) binding protein produced by human HEP G2 hepatoma cells has been deduced from the cDNA sequence. The 234 amino acid protein has a predicted molecular mass of 25, 274 and contains a single, distinctive cysteine-rich region. The N-ter-minal sequence of this protein is quite similar to the limited sequence data available for a rat IGF binding protein produced by BRL-3A cells and suggests a common ancestral origin. In contrast, the HEP G2 IGF binding protein sequence bears no similarity to the N-terminal 15 amino acids of a 53 kilodalton binding protein purified from human plasma. Comparison of full-length protein sequences for the IGF-I and IGF-II receptors with that of the HEP G2 IGF binding protein also fails to demonstrate any significant similarities among these three proteins, and suggests that each contains a unique binding domain for the IGF peptides.

Original languageEnglish (US)
Pages (from-to)404-411
Number of pages8
JournalMolecular Endocrinology
Volume2
Issue number5
DOIs
StatePublished - May 1988
Externally publishedYes

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ASJC Scopus subject areas

  • Molecular Biology
  • Endocrinology

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