Partial purification and characterization of a neutral insulin-like growth factor. Biochemical and biological properties.
A peptide with an isoelectric point of 6.5-7.0 was purified from Cohn fraction IV on the basis of its capacity to cross react with labelled insulin to human placental cell membrane receptors. It possesses insulin-like activity in the adipocyte bioassay (30 mU insulin equivalent/mg of protein) which is in the same order as its activity in the insulin radioreceptorassay (25.5 mU/mg). Somatomedin bioactivity is 40 U/mg in the porcine cartilage assay. In contrast, although in quiescent human fibroblast this peptide preparation has 6% of the mitogenic potency of somatomedin-C/insulin-like growth factor I on a weight basis, cross-reactivity in radioimmunoassay for somatomedin-C/insulin-like growth factor I, insulin-like growth factor II and insulin are very low. It is concluded that this peptide, although exhibiting the major biological characteristics of an insulin-like growth factor is different from the hitherto described somatomedins.
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007525:Isoelectric Focusing; D007700:Kinetics; D008297:Male; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D011972:Receptor, Insulin / Q000378:metabolism*; D013002:Somatomedins / Q000302:isolation & purification* / Q000494:pharmacology
D013002:Somatomedins; D011972:Receptor, Insulin; D005947:Glucose