saa1

Serum Amyloid A1 Protein (SAA1) is an acute phase apolipoprotein reactant that is produced predominantly by hepatocytes and is under the regulation of inflammatory cytokines. SAA is produced mainly in the liver and circulates in low levels in the blood. SAA may play a role in the immune system and facilitate the repair of injured tissues, it also acts as an antibacterial agent, and signals the migration of germ-fighting cells to sites of infection. SAA also functions as an apolipoprotein of the HDL complex. The SAA cleavage product designated amyloid protein A is deposited systemically as amyloid in vital organs such as the liver, spleen, and kidneys in chronic inflammatory diseases patients. These deposits are extremely insoluble and resistant to proteolysis; they disrupt tissue structure and compromise performance.

Major acute phase reactant. Apolipoprotein of the HDL complex. SAA1 Protein, Bovine, Recombinant (His) is expressed in E. coli expression system with N-6xHis tag. The predicted molecular weight is 18.6 kDa and the accession number is P35541.

Major acute phase reactant. Apolipoprotein of the HDL complex. SAA1 Protein, Feline, Recombinant (B2M & His) is expressed in E. coli expression system with N-6xHis-B2M tag. The predicted molecular weight is 24.1 kDa and the accession number is P19707.

Major acute phase reactant. Apolipoprotein of the HDL complex. SAA1 Protein, Canine, Recombinant (GST & His) is expressed in E. coli expression system with N-6xHis-GST tag. The predicted molecular weight is 42.5 kDa and the accession number is P19708.

Major acute phase reactant. Apolipoprotein of the HDL complex. SAA1 Protein, Horse, Recombinant (His) is expressed in E. coli expression system with N-10xHis tag. The predicted molecular weight is 15.8 kDa and the accession number is P19857.

Major acute phase protein. SAA1 Protein, Mouse, Recombinant (His) is expressed in E. coli expression system with N-6xHis tag. The predicted molecular weight is 17 kDa and the accession number is P05366.

Major acute phase reactant. Apolipoprotein of the HDL complex. SAA1 Protein, Sheep, Recombinant (His) is expressed in E. coli expression system with N-6xHis tag. The predicted molecular weight is 18.7 kDa and the accession number is P42819.

Major acute phase reactant. Apolipoprotein of the HDL complex. SAA1 Protein, Feline, Recombinant (His) is expressed in yeast with N-6xHis tag. The predicted molecular weight is 12.1 kDa and the accession number is P19707.

Serum amyloid A-2 protein (SAA2) belongs to the SAA family. It expressed by the liver and secreted in plasma. SAA2 functions as major acute phase reactant and could works as apolipoprotein of the HDL complex. Increased levels of A-SAA in serum are indicative of inflammatory disease. When highly expressed, SAA can displace ApoA1 as the major apolipoprotein in HDL complexes, weakening the function of HDL as a reverse (lipid clearing) cholesterol transporter. A highly charged region of SAA2 and SAA1 (aa 36-68) contains putative fibronectin- and laminin-binding motifs. This region also binds heparin sulfate proteoglycans at mildly acidic pH and promotes aggregation of A-SAA.

SAA4 is a member of the SAA family. SAA proteins are family of apolipoproteins of high density lipoprotein (HDL). They can be separated into two distinct groups. First group (SAA1, SAA2, and SAA3) consists of acute phase reactant whose expression level increase in the blood in a response to trauma, infection, inflammation, and neoplasia. These acute phase SAAs associates with HDL during inflammation and remodel the HDL particle by displacing Apo-A1. The second distinct group consists of SAA4 and SAA5 which exist as the minor apolipoproteins on HDL, but this group of SAA constitutes more than 90% of all the SAA during homeostasis, and it is thought to play a role in the normal functioning of the HDL particle. SAA4 is a constitutively expressed protein which expressed only in humans and mice. It is connected almost completely with lipoproteins of the high density range. The physiological function of SAA4 is unknown, and its serum concentration has no association with those of other major apolipoproteins.