Serum amyloid P component conserved in all vertebrates and also found in distant invertebrates such as the horseshoe crab (Limulus polyphemus). Serum amyloid P component The serum amyloid P component (SAP) is the identical serum form of amyloid P component (AP), a 25kDa pentameric protein first identified as the pentagonal constituent of in vivo pathological deposits called "amyloid". APCS is its human gene. AP makes up 14% of the dry mass of amyloid deposits and is thought to be an important contributor to the pathogenesis of a related group of diseases called the Amyloidoses. These conditions are characterised by the ordered aggregation of normal
Diego antigen system Diego antigen system The Diego antigen (or blood group) system is composed of 21 blood factors or antigens carried on the Band 3 glycoprotein, also known as Anion Exchanger 1 (AE1). The antigens are inherited through various alleles of the gene SLC4A1 (Solute carrier family 4), located on human chromosome 17. The AE1 glycoprotein is expressed only in red blood cells and, in a shortened form, in some cells in the kidney. The Diego antigen is fairly common in Indigenous peoples of the Americas (in both North and South America) and East Asians, but very rare or absent in most