Biosynthesis of soluble elastin by pig aortic tissue in vitro.

Incubation of normal newborn pig aorta with [14C]valine yielded a labeled protein that was isolated and purified with salt-soluble elastin from copper-deficient pig aorta as carrier. The labeled protein is soluble in strong neutral salt solution in the cold. It coacervates reversibly and can be separated into a hydrophobic phase by centrifugation at 32-37”. The protein migrates on polyacrylamide gel electrophoresis in 6 M urea with a relative mobility of 0.066 f 0.005. The molecular weight and hydrophobic properties identify the newly synthesized protein with soluble elastin. The comparably high specific activity of the insoluble elastin isolated from the incubation mixture indicates that the soluble protein is a rapidly cross-linked precursor of insoluble elastin.