Prothrombin/Factor II, human

Antibody	Host	Catalogue No.	Size	Product Insert
Purified IgG	Sheep	SAFII-IG	10 mg
Affinity purified IgG	Sheep	SAFII-AP	0.5 mg
Peroxidase conjugated IgG	Sheep	SAFII-HRP	0.2 mg
Matched Pair Antibodies for EIA		FII-EIA	5 plates

Prothrombin Fragments, human

Antibody	Host	Catalogue No.	Size	Product Insert
Fragment -1, affinity purified IgG	Sheep	SAFII-F1AP	0.5 mg
Fragment -2, affinity purified IgG	Sheep	SAFII-F2AP	0.5 mg

Description of Prothrombin – Factor II

Prothrombin (factor II, F.II) is a vitamin K-dependent glycoprotein produced in the liver.  The concentration of prothrombin in plasma is ~100 μg/ml (~1.4 μM).  Prothrombin is a single chain molecule with a molecular weight of 72 kDa.  Prothrombin consists of a catalytic domain followed by two kringle structures and an amino-terminal domain containing 10 γ-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 α-thrombin (37 kDa) and the by-product prothrombin fragment 1.2 (35 kDa).  The product thrombin further cleaves prothrombin fragment 1.2 after residue Arg155 into individual prothrombin fragments 1 and 2.  The activity of α-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 α₂macroglobulin and α₁antitrypsin^1-3.

References and Reviews

1. 1. Mann KG; Prothrombin and Thrombin; in Hemostasis and Thrombosis, 3^rd Edition, eds. RW Colman, J Hirsh, VJ Marder and EW Salzman, pp. 184-199, J.B. Lippincott Co., Philadelphia PA, USA, 1994.
2. 2. Mann KG; Prothrombin; Methods in Enzymology 45, pp 123-156, 1976.
3. 3. Downing MW, Bloom JW, Mann KG; Comparison of the Inhibition of Thrombin by Three Plasma Protease Inhibitors; Biochemistry 17, pp 2649-2653, 1978.

Related Products

• SAFII-IG Sheep anti-human FII, IgG from antiserum
• SAFII-HRP Sheep anti-human FII, IgG-peroxidase conjugate

• FII-EIA Paired antibody set for ELISA of Prothrombin/Factor II, 5 x 96 wells

• FII-DP Human plasma deficient in Prothrombin/Factor II, immune depleted

• INH2-DP Factor II Inhibitor Plasma, Frozen
• INH2-LDP Factor II Inhibitor Plasma, Lyophilized