Structural analogs of human insulin-like growth factor I with reduced affinity for serum binding proteins and the type 2 insulin-like growth factor receptor

Journal Article · Thu May 05 04:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:6838181

Bayne, M L; Applebaum, J; Chicchi, G G; Hayes, N S; Green, B G; Cascieri, M A

Four structural analogs of human insulin-like growth factor I (hIGF-I) have been prepared by site-directed mutagenesis of a synthetic IGF-I gene and subsequent expression and purification of the mutant protein from the conditioned media of transformed yeast. (Phe/sup -1/, Val/sup 1/, Asn/sup 2/, Gln/sup 3/, His/sup 4/, Ser/sup 8/, His/sup 9/, Glu/sup 12/, Tyr/sup 15/, Leu/sup 16/)IGF-I (B-chain mutant), in which the first 16 amino acids of hIGF-I were replaced with the first 17 amino acids of the B-chain of insulin, has >1000-, 100-, and 2-fold reduced potency for human serum binding proteins, the rat liver type 2 IGF receptor, and the human placental type 1 IGF receptor, respectively. The B-chain mutant also has 4-fold increased affinity for the human placental insulin receptor. (Gln/sup 3/, Ala/sup 4/) IGF-I has 4-fold reduced affinity for human serum binding proteins, but is equipotent to hIGF-I at the types 1 and 2 IGF and insulin receptors. (Tyr/sup 15/, Leu/sup 16/) IGH-I has 4-fold reduced affinity for human serum binding proteins and 10-fold increased affinity for the insulin receptor. The peptide in which these four-point mutations are combined, (Gln/sup 3/, Ala/sup 4/, Tyr/sup 15/,Leu/sup 16/)IGF-I, has 600-fold reduced affinity for the serum binding proteins. All four of these mutants stimulate DNA synthesis in the rat vascular smooth muscle cell line A10 with potencies reflecting their potency at the type 1 IGF receptor. These studies identify some of the domains of hIGF-I which are responsible for maintaining high affinity binding with the serum binding protein and the type 2 IGF receptor. In addition, These peptides will be useful in defining the role of the type 2 IGF receptor and serum binding proteins in the physiological actions of hIGF-I.

• Research Organization: Merck Sharp and Dohme Research Labs., Rahway, NJ (USA)
• OSTI ID: 6838181
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:13; ISSN JBCHA
• Country of Publication: United States
• Language: English

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550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AZINES
BETA DECAY RADIOISOTOPES
BIOCHEMISTRY
CHEMISTRY
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
GENE MUTATIONS
GENES
GROWTH FACTORS
HETEROCYCLIC COMPOUNDS
HORMONES
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MAN
MEMBRANE PROTEINS
MITOGENS
MUTAGENESIS
MUTATIONS
NUCLEI
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ODD-EVEN NUCLEI
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDE HORMONES
PRIMATES
PROTEINS
PURIFICATION
PYRIMIDINES
RADIOISOTOPES
RECEPTORS
RIBOSIDES
THYMIDINE
TRITIUM COMPOUNDS
VERTEBRATES