Amino acid composition and calcification of human aortic elastin

Abstract

Hot alkali purified elastin derived from areas of calcified plaques in human thoracic aortas was markedly and consistently more polar in amino acid composition than similarly prepared elastin from non-plaque areas of the same vessel. These changes in composition reflected a persistent contamination of the elastin by a second, more polar protein as well as by some collagen. The extent of this contamination was correlated with the ash content of the elastic tissue. Decalcification of the elastic tissue prior to hot alkali treatment resulted in an elastin residue of the composition of “pure” elastin even from previously heavily contaminated plaque tissue. The authors conclude that the change in amino acid composition of human aortic elastin with age and in the areas of arteriosclerotic plaques is a consequence of the increased presence of calcium crystallites in the tissue.