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Serum Amyloid A Isoforms in Inflammation
Author(s) -
RAYNES J. G.,
McADAM K. P. W. J.
Publication year - 1991
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1991.tb02538.x
Subject(s) - gene isoform , serum amyloid a , amyloidosis , arginine , isoelectric focusing , serum amyloid a protein , amyloid (mycology) , chemistry , pi , isoelectric point , inflammation , medicine , endocrinology , biochemistry , amino acid , biology , enzyme , inorganic chemistry , gene
Serum amyloid A protein (SAA) was extracted from serum using hydrophobic interaction chromatography and four or six isoforms were separated by isoelectric‐focusing. These represented three pairs of isoforms, each with and without an N‐terminal arginine. SAA I (pi 6.1). SAA l des‐arg (pl 5.9). SAA2α (pi 6.9) and SAAα: des‐arg (pl 6.6) were found to be present in all individuals from Europe and the USA. A minority of these individuals (11 of 56) expressed SAA2/β (pl 7. 1) and SAA2/β des‐arg (pi 6.8). Serum from patients in Papua New Guinea and Malawi both showed a much higher frequency ofSAA2/β. There was no indication of altered isoforms in regions with high incidence of reactive AA amyloidosis. In sequential serum samples, concentrations of des‐arg isoforms were found to reach a maximum 0 24 h later than isoforms with an arginine. Concentrations of the isoform SAA1 decreased faster in five of six patients (16±:7.5 h to decrease 50%) than SAAl des‐arg (22± 11 h to decrease 50%). Variations in the handling of N‐terminal arginine may be important for the formation‐susceptibility of amyloid deposits.