Serum amyloid P component 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 globular proteins and peptides into insoluble fibres which disrupt tissue architecture and are associated with cell death.
P-glycoprotein lumen, in liver cells where it pumps them into bile ducts, in the cells of the proximal tubule of the kidney where it pumps them into urinary filtrate (in the proximal tubule), and in the capillary endothelial cells composing the blood–brain barrier and blood-testis barrier, where it pumps them back into the capillaries. P-gp is a glycoprotein that in humans is encoded by the "ABCB1" gene. P-gp is a well-characterized ABC-transporter (which transports a wide variety of substrates across extra- and intracellular membranes) of the MDR/TAP subfamily. The normal excretion of xenobiotics back into the gut lumen by P-gp pharmacokinetically