Antiserum developed for the E peptide region of insulin-like growth factor IA prohormone recognizes a serum protein by both immunoblot and radioimmunoassay.
Nucleotide sequencing of the two known cDNAs encoding human insulin-like growth factor I (IGF-I) predicts two different prohormone forms of IGF-I. The predicted prohormone amino acid sequences (E peptide regions) extend the carboxy-terminus of IGF-I by either an additional 35 (IGF-IA) or 77 (IGF-IB) amino acids. We developed an antiserum directed against a synthetic peptide which is unique to the E peptide region of IGF-IA prohormone. In a RIA using this antiserum, synthetic E peptide immunoreactivity was found in the serum of patients with chronic renal failure. The protein recognized by this antiserum has a mol wt of about 13,000 by neutral gel filtration and about 19,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. These data suggest that the E peptide region of the IGF-IA prohormone is expressed and circulates as part of the prohormone.
Powell
D R
DR
Department of Pediatrics, Stanford University Medical Center, California 94305.
Lee
P D
PD
Chang
D
D
Liu
F
F
Hintz
R L
RL
D001798:Blood Proteins / Q000276:immunology*; D006801:Humans; D007106:Immune Sera / Q000276:immunology*; D007158:Immunologic Techniques; D007334:Insulin-Like Growth Factor I / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000276:immunology*; D011863:Radioimmunoassay; D013002:Somatomedins / Q000276:immunology*; D014511:Uremia / Q000097:blood
D001798:Blood Proteins; D007106:Immune Sera; D010446:Peptide Fragments; D013002:Somatomedins; C053766:insulin-like growth factor 1A prohormone (91-103); D007334:Insulin-Like Growth Factor I