High molecular weight forms of insulin-like growth factor II and its binding protein identified by protein immunoblotting.
Insulin-like growth factor (IGF)II is a mitogenic polypeptide which circulates in association with a binding protein(s). Immunoblotting studies were performed in human serum and indicate that:(1)a approximately 200 kDa covalently-linked IGF-II/binding protein complex is antigenically related to the 30 kDa binding protein, (2)IGF-II prohormone is associated with this complex, and (3)a major portion of the IGF-II prohormone immunoreactivity in human serum is present in fractions which would not be detected by standard radioimmunoassay methods. Our data provide insight regarding the inter-relationships of IGF-II and its binding protein, and direct evidence for the presence of IGF-II prohormone in human serum.
Lee
P D
PD
Children's Hospital Kempe Research Center, Denver, CO 80218.
Powell
D R
DR
Li
C H
CH
Bohn
H
H
Liu
F
F
Hintz
R L
RL
D006801:Humans; D007163:Immunosorbent Techniques; D007335:Insulin-Like Growth Factor II / Q000032:analysis*; D008722:Methods; D008970:Molecular Weight; D011972:Receptor, Insulin / Q000032:analysis*; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000032:analysis*
D017451:Receptors, Somatomedin; D013002:Somatomedins; D007335:Insulin-Like Growth Factor II; D011972:Receptor, Insulin