Protein Z

Overview

Illustration of Protein Z

Protein Z is a vitamin K-dependent plasma protein that plays a role in the regulation of blood coagulation. It is a glycoprotein that is primarily synthesized in the liver and circulates in the blood. Protein Z serves as a cofactor for the inhibition of activated factor X (Xa) by the protein Z-dependent protease inhibitor (ZPI).

Structure

Protein Z is a single-chain glycoprotein with a molecular weight of approximately 62 kDa. It consists of several domains, including a Gla domain, two EGF-like domains, and a C-terminal domain. The Gla domain is responsible for binding calcium ions, which is essential for its biological activity.

Function

The primary function of Protein Z is to enhance the inhibition of factor Xa by ZPI. This interaction is crucial for maintaining the balance between coagulation and anticoagulation in the blood. By inhibiting factor Xa, Protein Z helps to prevent excessive clot formation, which can lead to thrombosis.

Clinical Significance

Deficiency or dysfunction of Protein Z has been associated with an increased risk of thrombotic disorders, such as deep vein thrombosis and pulmonary embolism. Conversely, elevated levels of Protein Z have been observed in certain conditions, such as liver disease and pregnancy.

Genetics

The gene encoding Protein Z is located on chromosome 13 in humans. Variations in this gene can affect the levels and activity of Protein Z, influencing an individual's risk of developing coagulation disorders.

Related pages

• Coagulation
• Vitamin K
• Factor X
• Thrombosis
• Liver