sodium dodecyl sulfate-acrylamide gel electrophoresis and molecular-sieve chromatography on 8 % agarose demonstrate the existence of a very high molecular weight ( 500,000-600,000 ) , proline-rich protein in cultured 3t6 fibroblasts that appears to be the precursor molecule ( procollagen ) of collagen .
C0033235
procollagen
C0009325
collagen