Protein S is a vitamin K-dependent, potent neutral anticoagulant plasma glycoprotein.
Protein S has a molecular weight of approximately 70kD and concists of a single polypeptide chain.
The concentration of protein S in human plasma is 25ug/ml, with a half-life of approximately two days.
About 40% of Protein S in plasma is in a free form, whereas 60% is complexed with C4b-binding Protein (C4BP).
Only the free Protein S functions as a cofactor to antigen presenting cells (APC) in the APC-dependent degradation of Factor Va and Factor VIIIa.
Protein S is thought to function in both the coagulation and complement cascades.
It has been suggested that g-carboxyglutamic acid (gla) dependent binding of protein S to negatively charged phospholipids may function to concentrate C4BP at cell surfaces following injury.
In the coagulation system, Protein S functions as an anticoagulant cofactor protein.
Activated Protein C (APC) forms a 1:1 stoichiometric complex with Protein S in the presence of Ca2+ and phospholipid vesicles (Kd=6x10e-9M).
In the presence of Protein S, a moderate increase (3-10 fold) in the rate of factor Va and factor VIIIa inactivation by APC is observed in plasma and on the surface of unstimulated platelets.
Protein S bound to C4BP does not possess APC cofactor activity.
Recently, an additional binding protein which enhances the activity of Protein S has been described.
Proteolytic inactivation of Protein S by thrombin has been proposed as a regulatory mechanism in this system.
A single cleavage by thrombin abolishes Protein S cofactor activity by removing an NH2-terminal peptide (Mr=8000) which contains the gla domain.
The domain structure of Protein S is similar to that of the other vitamin K-dependent coagulation factors with the exception that Protein S does not possess the catalytic triad.
Protein S is a single chain protein containing 10 gla residues in the NH2-terminal domain and 4 epidermal growth factor (EGF) domains.
Applications:Suitable for use in Immunoelectrophoresis and ELISA.
Other applications not tested.
Recommended Dilution:ELISA: capture Optimal dilutions to be determined by the researcher.
Storage and Stability:May be stored at 4°C for short-term only.
Aliquot to avoid repeated freezing and thawing.
Store at -20°C.
Aliquots are stable for 12 months after receipt.
For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
仕様
Size：500ug
Host：sheep
Source Antibody：human
Grade：Affinity Purified
Purity：Purified by immunoaffinity chromatography.
Form：Supplied as a liquid in 0.01M HEPES, pH 7.4, 0.15M sodium chloride and 50% glycerol.
Specificity：Recognizes human Protein S.
Isotype：IgG
Calc Applications Abbrev：E
Calc Crossreactivity：Hu
Immunogen：Human Protein S (PS) purified from plasma.
