Serum amyloid P component in mink, a non-glycosylated protein with affinity for phosphorylethanolamine and phosphorylcholine.
Experimental AA amyloidosis in the mink is used as a model for the amyloid disease process. In that context it is important to characterize the different proteins involved in the amyloid formation. In the present work, we have characterized the serum amyloid P component (SAP) in mink. SAP was purified from serum by affinity chromatography using phosphorylethanolamine-coupled ECH-sepharose 4B. SDS-PAGE showed one major protein band (approximately 26 kDa) together with one minor band (10% of the major band) with a higher molecular mass (approximately 30 kDa) corresponding to a non-glycosylated and a glycosylated variant. All SAP molecules elucidated so far have at least one major subunit that is heavily glycosylated. It is therefore the first time that a non-glycosylated SAP protein is found in a mammalian species. The amino acid sequence was established using Edman degradation and mass spectrometry. As expected, the protein showed high homology with the other mammalian SAP molecules, ranging from 73% (human) to 63% (mouse). The SAP protein showed affinity for phosphorylcholine and thus expressed CRP-like properties.
Department of Rheumatology/Institute of Immunology, Rikshospitalet, University of Oslo, Blindern, Norway. l.a.omtvedt@biotek.uio.no
Lone A
LA
Omtvedt
Tale N
TN
Wien
Theresa
T
Myran
Knut
K
Sletten
Gunnar
G
Husby
D000595:Amino Acid Sequence; D000686:Amyloidosis / Q000378:metabolism*; D000818:Animals; D002846:Chromatography, Affinity; D004983:Ethanolamines / Q000378:metabolism*; D005260:Female; D006031:Glycosylation; D008297:Male; D008907:Mink / Q000097:blood*; D008969:Molecular Sequence Data; D010767:Phosphorylcholine / Q000378:metabolism*; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D000683:Serum Amyloid P-Component / Q000378:metabolism*
D004983:Ethanolamines; D000683:Serum Amyloid P-Component; D010767:Phosphorylcholine; C005448:phosphorylethanolamine