Constitution of the Cross-linkages in Elastin

Abstract

ELASTIN is insoluble in all reagents except those which break peptide bonds, and when wet the protein behaves as a typical rubber-like solid¹. These characteristics, together with the swelling properties, are consistent with the view that elastin can be regarded as a cross-linked polymer gel containing long peptide chains randomly crumpled and held laterally at intervals by strong chemical bonds². In an attempt to isolate small regions of the peptide network containing the cross-links, Thomas and Partridge³ degraded the protein by use of a succession of proteolytic enzymes followed by amino- and carboxy-peptidases. The product consisted of amino-acids and small peptides together with a fraction of higher molecular weight. This fraction was isolated and was found to be bright yellow in colour with the blue-white fluorescence characteristic of elastin fibres.