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.
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-terminal 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.
Lee
Y L
YL
Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77054.
Hintz
R L
RL
James
P M
PM
Lee
P D
PD
Shively
J E
JE
Powell
D R
DR
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004273:DNA, Neoplasm / Q000235:genetics; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D008969:Molecular Sequence Data; D011972:Receptor, Insulin; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000235:genetics / Q000302:isolation & purification; D014407:Tumor Cells, Cultured
D002352:Carrier Proteins; D004273:DNA, Neoplasm; D018969:Insulin-Like Growth Factor Binding Proteins; D017451:Receptors, Somatomedin; D013002:Somatomedins; D011972:Receptor, Insulin; D004262:DNA Restriction Enzymes