Comparative studies of the high molecular weight amyloid fibril proteins and similar components from normal tissues

Abstract

Analysis of purified amyloid fibrils by gel filtration, polyacrylamide gel electrophoresis in SDS and 8 M urea, and immunodiffusion and immunoelectrophoresis showed that, in addition to the specific amyloid proteins AA and AL, the amyloid preparations all contain a high molecular weight complex. The latter protein complex contains fibronectin, a component which reacts with a non-AA specificity of an antiserum to degraded AA amyloid fibrils (termed the 'B' specificity), and a high molecular weight component excluded by a Sepharose 2BCL column. Similar components were found in aqueous extracts of normal tissues prepared by an identical procedure, and these form aggregates of different size in non-dissociating conditions. It is suggested that amyloid fibrils are complexes of a variety of macromolecules in addition to the specific proteins AA and AL.