A high molecular weight serum protein is the carrier for amyloid-related protein SAA

In the present study evidence is presented that SAA in serum complexes to a carrier protein with a molecular weight of 100,000-200,000 daltons, with mobility in the alpha-region on electrophoresis, and with a rather low normal serum concentration. The carrier protein is apparently not albumin. SAA isolated from the carrier protein has a molecular weight of 14,000 daltons and does not complex to any considerable extent with itself under neutral conditions.