glycoprotein deposited extracellularly in tissues in amyloidosis. The glycoprotein may either derive from light chain of immunoglobulin (AIO (amyloid of immune origin): 5-18 kd glycoprotein, product of a single clone of plasma cells, the N terminal part of lambda or kappa light chain) or, in what used to be referred to as AUO, amyloid of unknown origin, from serum amyloid a (SAA), one of the acute phase proteins that increases many fold in inflammation. The polypeptides are organised as a _ pleated sheet making the material rather inert and insoluble. Minor protein components are also found. Should be distinguished from _ amyloid deposited in the brain and that is derived from amyloid precursor protein (see amyloidogenic glycoprotein.