Purification of a basic somatomedin, from human plasma Cohn fraction IV-1, with physicochemical and radioimmunoassay similarity to somatomedin-C and insulin-like growth factor.
A basic somatomedin (SM) was purified from human plasma Cohn fraction IV-1 using an initial acid--ethanol--acetone extraction procedure followed by alternating molecular size or charge protein separation techniques. The final recovery of SM bioactivity was approximately 2% of that present in the starting Cohn fraction. The purified SM has an approximate molecular weight of 7500, pI 8.6, 4000 SM bioactivity units per milligram (as measured by a hypophysectomized rat bioassay) and a parallel approximately equipotent radioimmunoassay dose--response curve to SM-C and insulin-like growth factor-1 (IGF-I). Sodium dodecyl sulfate--polyacrylamide gel electrophoresis of this purified SM revealed a single protein band. The preliminary determination of the amino acid sequence of the N terminus suggested that this SM preparation was over 75% pure and the first five N-terminal amino acids were identical with those of IGF-I.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007525:Isoelectric Focusing; D008297:Male; D008970:Molecular Weight; D011247:Pregnancy; D011817:Rabbits; D011863:Radioimmunoassay; D013002:Somatomedins / Q000302:isolation & purification*
D000596:Amino Acids; D013002:Somatomedins