Isolation and Properties of Soluble Elastin from Copper-deficient Chicks

Abstract

A soluble elastin-like protein was isolated from the aortas of copper-deficient chicks. The protein was purified after formic acid extraction, ammonium sulfate precipitation, dissolution in propanol-butanol and chromatography on columns of Sephadex G-100. Electrophoresis on polyacrylamide gels indicated that the material was free of soluble collagens. The amino acid composition of the material resembled that of insoluble elastin but contained 48 residues of lysine per thousand and no desmosine and isodesmosine. Almost all of the lysine in the protein appeared to react readily with carbonyl functions. The protein coacervated at room temperature, but was soluble below 8°. The material may be a probable precursor of insoluble elastin in aortic tissue and could only be obtained from chicks that were copper-deficient. In addition, copper-deficiency resulted in low levels of lysyl oxidase and collagen solubility was increased threefold in tendon. Mortality due to aortic rupture and internal hemorrhage was greater than 40% in the deficient groups. These data confirm observations which have been previously reported in studies on copper-deficient swine.