10] Isolation and characterization of insoluble and soluble elastins

Abstract

This chapter discusses isolation and characterization of insoluble and soluble elastins. Elastin demonstrates remarkable functionality, correlating with macroscopic and microscopic structure and with molecular composition. Its ubiquitousness necessitates our understanding of these relationships, because tissue-specific extraction methods are necessary for its purification. Lack of agreement on criteria of purity stems from its complex supramolecular organization and intricate relationships with other macromolecules primarily of connective tissues. Purity is assessed by absence of collagen and collagen-like features (methionine, hydroxylysine, high hydroxyproline), absence of carbohydrate, presence of high content of non polar amino acids (glycine, alanine, proline, valine), and low content of polar amino acids (aspartate, glutamate, lysine, histidine, arginine).this chapter also provides assessment of results of various major methods. Immunologic methods such as radio immunoprecipitation and rocket immunoelectrophoresis may prove to be at least as sensitive in determining the amount of material present. However, because of the insoluble nature of mature elastin, many of these methods are not useful unless elastin is present in a degraded soluble form. Cross-link analysis may also be helpful for quantitation if hydrolyzed samples can be used.