Amyloid fibril protein in type I familial amyloidotic polyneuropathy in Japanese.

Amyloid fibrils were isolated from the kidneys of two Japanese patients with type I FAP and fractionated on Sephadex G-100 gel column. The elution pattern showed three peaks. Molecular weight of the third peak protein was about 14,000, which was absent in the chromatogram obtained from the tissue of a nonamyloidotic patient. Antisera raised against whole denatured amyloid fibril components reacted with this protein, giving rise to a precipitin arc on immunoelectrophoretic analysis in the area almost corresponding to prealbumin but slightly cathodal to it. The amino acid composition of this protein was different from those of AA protein. AL protein, or normal human PreA subunit. The major subunit GAM III of amyloid fibril protein (AFj) appears immunologically related to PreA.