Prothrombin (factor II, F.II) is a vitamin K-dependent glycoprotein produced in the liver.
The concentration of prothrombin in plasma is ~100ug/ml (~1.4uM).
Prothrombin is a single chain molecule with a molecular weight of 72kD.
Prothrombin consists of a catalytic domain followed by two kringle structures and an amino-terminal domain containing 10 y-carboxy-glutamic acid (gla) residues.
These gla residues allow prothrombin to bind to membranes that contain acidic phospholipids in a calcium dependent manner.
The binding to membranes is required for effective presentation of prothrombin as a substrate for activation by the prothrombinase complex, which consists of activated factor X, activated cofactor V and calcium on phospholipid membrane.
Activation by prothrombinase occurs by sequential cleavage after residue Arg320 then after Arg271 to produce the active protease a-thrombin (37kD) and the byproduct prothrombin fragment 1.2 (35kD).
The product thrombin further cleaves prothrombin fragment 1.2 after residue Arg155 into individual prothrombin fragments 1 and 2.
The activity of a-thrombin in plasma is inhibited primarily by antithrombin and the rate of inhibition is accelerated 1000-fold in the presence of optimal concentrations of heparin.
Other physiological inhibitors of thrombin in the absence of heparin include a2macroglobulin and a1antitrypsin.
Applications:Suitable for use in ELISA.
Other applications not tested.
Recommended Dilutions:Optimal dilutions to be determined by the researcher.
