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EXTRACTION AND PROTEIN SEQUENCING OF IMMUNOGLOBULIN LIGHT CHAIN FROM FORMALIN‐FIXED CEREBROVASCULAR AMYLOID DEPOSITS
Author(s) -
LAYFIELD ROBERT,
BAILEY KEVIN,
LOWE JAMES,
ALLIBONE RICHARD,
MAYER R. JOHN,
LANDON MICHAEL
Publication year - 1996
Publication title -
the journal of pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.964
H-Index - 184
eISSN - 1096-9896
pISSN - 0022-3417
DOI - 10.1002/(sici)1096-9896(199612)180:4<455::aid-path692>3.0.co;2-3
Subject(s) - cyanogen bromide , immunoglobulin light chain , amyloidosis , antibody , amyloid (mycology) , chemistry , amino acid , peptide sequence , peptide , microbiology and biotechnology , biochemistry , biology , pathology , medicine , immunology , gene , inorganic chemistry
Substantial amounts of a single protein have been extracted into electrophoresis sample buffer from archived formalin‐fixed brain blood vessels, taken from a case of cerebral amyloidosis. Cyanogen bromide cleavage and tryptic digestion of the protein on Western blots allowed amino acid sequences from three resultant peptides to be determined. Comparison of these peptides with database sequences identified the extracted protein as being derived from an immunoglobulin light chain. This is the first demonstration of amino acid sequencing of a polypeptide extracted from formalin‐fixed tissue. This case also appears to be unique, since primary cerebrovascular amyloidosis involving immunoglobulin light chains has not been previously described. The amyloid protein had clearly resisted formalin fixation; it is possible that this resistance occurred because the protein was deposited in large amounts as insoluble densely packed aggregates, which may exclude infiltration of the formalin. This technique may therefore have applications in the post‐mortem diagnosis of amyloidoses and in the purification of other amyloids.