title: Amyloid protein SAA is associated with high density lipoprotein from human serum.
abstract: Human serums contain a protein antigenically related to protein AA, the principal protein of a major class of amyloid substance. The serum antigen, SAA, occurs mainly in a high molecular weight form, 1 to 2 X 10(5). This work shows that the bulk of the SAA sediments at density 1.12 g/cm3 and floats at density 1.21 g/cm3, as does the high density lipoprotein HDL3. SAA is associated with the apolipoproteins ApoA-I and ApoA-II. The total cholesterol:total protein ratio of the fraction with density 1.12-1.21 g/cm3 is 0.2:1, consistent with that of SAA constituent of the HDL3 fraction into low molecular weight species of the order of 13,000. The quantity of SAA may vary from 0.1% or more of the total protein of HDL3.
mesh_terms: D000682:Amyloid / Q000097:blood*; D001798:Blood Proteins; D006801:Humans; D005779:Immunodiffusion; D008075:Lipoproteins, HDL / Q000097:blood*; D008099:Liver / Q000032:analysis; D011485:Protein Binding; D011863:Radioimmunoassay
chemical_list: D000682:Amyloid; D001798:Blood Proteins; D008075:Lipoproteins, HDL