Information AboutProtein Z |
| CATEGORIES ABOUT PROTEIN Z | |
| coagulation system | |
Protein Z is a member of the Coagulation Cascade , the group of blood proteins that leads to the formation of Blood Clot s. It is Vitamin K -dependent, and its functionality is therefore impaired in Warfarin therapy. It is a Glycoprotein . PHYSIOLOGY Although it is not enzymatically active, it is structurally related to several , IX and X . The carboxyglutamate residues (which require vitamin K) bind protein Z to Phospholipid surfaces. The main role of protein Z appears to be the degradation of Factor X a. This is done by Protein Z-related Protease Inhibitor (ZPI), but the reaction is accelerated 1000-fold by the presence of protein Z. Oddly, ZPI also degrades Factor XI , but this reaction does not require the presence of protein Z. In some studies, deficiency states have been associated with a propensity to Thrombosis . Others, however, link it to Bleeding Tendency ; there is no clear explanation for this, as it acts physiologically as an inhibitor, and deficiency would logically have led to a predisposition for Thrombosis . GENETICS It is 62 KDa large and 396 Amino Acid s long. The ''PROZ'' Gene has been linked to the thirteenth Chromosome (13q34). It has four domains: a gla-rich (carboxyglutamate) region, two EGF-like domains and a trypsin-like domain. It lacks the Serine residue that would make it catalytically active as a Serine Protease . HISTORY Protein Z was first isolated in Cattle blood by Prowse and Esnouf in 1977, and Broze & Miletich determined it in human plasma in 1984. REFERENCES
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