Haematologic Technologies - Beta Thrombin, Gamma Thrombin

PROTEOLYZED FORMS OF α-THROMBIN The degradation pattern of human α-thrombin to less active forms is illustrated above. β-thrombin is generated by cleavage of the intact B-chain at the Arg₁₀₆-Tyr₁₀₇ bond to yield the B1 and B2 fragments. γ-thrombin is generated by further cleavage of the β-thrombin B2-chain at the Lys₁₉₀-Gly₁₉₁ bond to yield the B4 and B5 fragments. Although not illustrated, the B3 fragment is a potential intermediate that is derived by cleavage of the intact B-chain at the Lys₁₉₀-Gly₁₉₁ bond, resulting in a product that is often referred to as β'-thrombin. (The amino acid numbering used here begins at the NH₂-terminal end of the A-chain and continues through the B-chain).

PURCHASING AND PRODUCT INFORMATION

Catalog Number

HCBT-0022

HCGT-0021

Description

Human b-Thrombin

Human g-Thrombin

Size

100 µg

Formulation

10 mM NaPO₄, 0.3 M NaCl, pH 6.5

100 mM NaPO₄, 0.1% PEG, pH 6.5

Storage

-80^oC

Purity

>95% by SDS-PAGE

Activity Determination

Fibrinogen clotting assay

Shelf Life (properly stored)

12 months

Beta Thrombin

Gamma Thrombin

Sample Gel Information:

Gel: Novex 4-12% Bis-Tris

Load: Human Beta & Gamma Thrombin, 1 µg per lane

Buffer: MES

Standard: SeeBluePlus 2; Myosin (188 kDa), Phosphorylase B (98 kDa), BSA (62 kDa), Glutamic Dehydrogenase (49 kDa), Alcohol Dehydrogenase (38 kDa), Carbonic Anhydrase (28 kDa), Myoglobin Red (17 kDa), Lysozyme (14 kDa), Aprotinin (6 kDa), Insulin, B chain (3 kDa).

Note: Other contaminants are of thrombin origin, and may make up to ~5% of the additional band mass.

U.S. Pricing

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SAMPLE DATA SHEETS

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Overview of Beta and Gamma Thrombin

Alpha-thrombin is a highly specific serine protease generated by proteolytic activation of the zymogen prothrombin (1). Purified forms of α-thrombin have been shown (2-4) to undergo autolysis upon long term storage to less active forms. Similar inactivation was observed upon limited digestion of a-thrombin with trypsin (5). These proteolyzed forms of α-thrombin have been termed β-thrombin and γ-thrombin. Human β-thrombin is generated by cleavage of the B-chain at the Arg106-Tyr107 bond. γ-thrombin is generated by further cleavage of the β-thrombin B2-chain at the Lys190-Gly191 bond. Another form of proteolyzed thrombin, termed β'-thrombin is formed by the single cleavage of thrombin at Arg-154. γ-thrombin is produced by proteolytic cleavage at both of these sites (Arg70/73 and Arg-154) in the B-chain. These cleavages cause release of peptides that are no longer covalently attached to the thrombin molecule, but remain associated through ion exchange and gel filtration chromatography. These proteolyzed forms of thrombin retain their ability to cleave small synthetic substrates (6,7) and some protein substrates such as factor XIII (8), antithrombin III (9) and prothrombin (10). Their ability to clot fibrinogen (11), cleave thrombospondin (12) or activate protein C (9) have been markedly decreased.

Human β-thrombin and γ-thrombin are prepared from purified a-thrombin by limited proteolysis with TPCK-treated trypsin, essentially by the method of Braun et al. (5). The proteolyzed forms of a-thrombin are supplied in 100 mM NaH2PO4, pH 6.5 buffer and should be stored at -20ºC. Purity is assessed by SDS-PAGE and activity is assessed using a fibrinogen clotting assay.

Properties of β and γ-Thrombin

Mode of action:

Proteolyzed forms of -thrombin which retain activity toward small substrates, factor XIII and prothrombin, but have reduced activity toward fibrinogen, protein C activation and antithrombin III binding.

Molecular weight:

36,700 (b-thrombin)
36,700 (g-thrombin)

4,000 (A chain)*

34,300 (B chain)*

6,000 (B1 chain)*

10,400 (B5 chain)*

11,800 (B4 chain)*

* Apparent molecular weight as determined by SDS-PAGE analysis

Extinction coefficient:

1 %

1 c m, 280 nm

= 18.3

Structure:

b-thrombin: three chains (A, B1, B2), disulfide link between the A and the B2 chains. g-thrombin: four chains (A, B1, B5, B4) with a disulfide link between the A peptide and the B5 peptide.

References

1. Lundblad, R.L., et al., Methods Enzymol., 45, 156 (1976).
2. Lundblad, R.L., et al., J. Biol. Chem., 254, 8524 (1979).
3. Fenton, J.W., et al., in Chemistry and Biology of Thrombin, ed. R.L. Lundblad, J.W. Fenton, K.G. Mann, pp. 43-70, Ann Arbor, MI: Ann Arbor Science Publishers, Inc., 1977.
4. Boissel, J.P., et al., J. Biol. Chem., 259, 5691 (1984).
5. Braun, P.J., et al., Thromb. Res., 50, 273 (1988).
6. Lottenberg, R., et al., Thromb. Res., 28, 313 (1982).
7. WittiNg, et al., Thromb. Res., 46, 567 (1987).
8. Lorand, L. and Credo, R.B., in Chemistry and Biology of Thrombin, ed. R.L. Lundblad, J.W. Fenton, K.G. Mann, pp. 311-323, Ann Arbor, MI: Ann Arbor Science Publishers, Inc., 1977.
9. Bezeaud, A., et al., Eur. J. Chem., 153, 491 (1985).
10. Seegers, W.H., et al., Semin. Thromb. Haemostasis, 1, 211 (1975).
11. Lundblad, R.L., et al., J. Biol. Chem., 259, 6991 (1984).
12. Takahashi, K., et al., Biochem. J., 224, 673 (1984).