Serum amyloid A proteins (SAA) represents a family of apolipoproteins that circulates in association with high-density lipoproteins (HDL). The level of apo-SAA, normally 1-5 ug/ml in plasma, increases 500-1000 fold within 24 hours of an inflammatory stimulus and, under these conditions, is the most abundant HDL apo-lipoprotein. The human SAA gene codes for a 122 amino acid nonglycosylated polypeptide, which contains an 18 amino acid N-terminal sequence. Alternative Names: Apo SAA-1 protein, Human Serum Amyloid A protein, ApoSAA-1, ApoSAA-1 protein, ApoSAA 1 protein, ApoSAA 1, ApoSAA1