serpina 3

Serpin A5 is a member of the human Serpin superfamily consists of at least 35 members. It is synthesized in the liver and has been detected in saliva, cerebral spinal fluid, amniotic fluid, tears and semen. As a potent inhibitor of the protein C anticoagulant pathway at the levels of both zymogen activation and enzyme inhibition, Serpin A5 additionally inhibits a variety of serine protease including thrombin, factor Xa, several kallekreins and acrosin. It plays a critical role in the processes of blood of blood coagulation and fertilization. Serpin A5 also inhibits urinary plasminogen activator (uPA), a mediator of tumor cell invasion, and regulates tumor growth and metastasis by inhibiting angiogenesis. Furthermore, recent studies have identified PCI as a potent and direct inhibitor of activated HGFA (hepatocyte growth factor activator), suggesting a novel function in the regulation of tissue repair and regeneration. Similar to Serpins C1 and D1, the thrombin inhibitory activity of serpinA5 is enhanced by heparin.

SerpinA3, also known as Alpha 1-antichymotrypsin (AACT), is a plasma alpha globulin glycoprotein, and is a member of serpin superfamily of the serine protease inhibitors consisting of at least 35 members. SerpinA3 has been demonstrated to inhibit the activity of certain serine proteases, such as cathepsin G found in neutrophils, and chymases present in mast cells, by inducing a major conformational rearrangement, and thus protects some tissues from damage caused by proteolytic enzymes. This enzyme is produced primarily in the liver, and is identified as an acute-phase inflammatory protein. SerpinA3 deficiency has been associated with liver disease, and mutations of this gene have been observed in patients with Parkinson disease and chronic obstructive pulmonary disease. Besides, ACT gene polymorphism has been implicated with Alzheimer’s disease (AD), cerebral amyloid angiopathy (CAA), as well as stroke, since SerpinA3 is a major constituent of the plaques in AD and an inhibitor of amyloid beta peptide degradation.