Protein Z-dependent protease inhibitor (ZPI) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

circulating in the

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

which inhibits factors Xa and XIa of the

coagulation cascade Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The mechanism ...

. It is a member of the class of the

serine protease inhibitor Serpins are a superfamily of proteins with similar structures that were first identified for their protease inhibition activity and are found in all kingdoms of life. The acronym serpin was originally coined because the first serpins to be i ...

s (serpins). Its name implies that it requires

protein Z Protein Z (PZ or PROZ) is a Protein in humans which is encoded by the ''PROZ'' gene. Protein Z is a member of the coagulation cascade, the group of blood proteins that leads to the formation of blood clots. It is a glycoprotein. Protein Z functi ...

, another circulating protein, to function properly, but this only applies to its inhibition of factor X. It is about 72

kDa The dalton or unified atomic mass unit (symbols: Da or u) is a non-SI unit of mass widely used in physics and chemistry. It is defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at re ...

heavy and 444

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

s large. It is produced by the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...

Role in disease

Water ''et al.'' found deficiency of ZPI in 4.4% of a cohort of patients with thrombophilia (a tendency to

thrombosis Thrombosis (from Ancient Greek "clotting") is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (t ...

History

Han ''et al.'' first described ZPI in 1998. The same group further characterised it in 2000.

References

External links

* The

MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett in 1993, and that for protein inhibit ...

online database for peptidases and their inhibitors
I04.005
{{DEFAULTSORT:Protein Z-Related Protease Inhibitor Coagulation system Serine protease inhibitors