The Stability of Tissue Plasminogen Activator (t-PA)

Summary

Since tissue-type plasminogen activator (t-PA) derived from tissue culture and recombinant DNA procedures has been proposed for use in thrombolytic therapy in man, it is essential that the t-PA molecule should display reasonable stability in a lyophilised state to facilitate its usefulness. In this study, four laboratories compared the potencies of three preparations of t-PA following storage at 4°, 20°, 37° and 45° C, using each t-PA stored at -20° C as a reference (100% activity) in each case. A pig heart extract of t-PA was the most stable, losing no activity when stored for 30 days at 37° C, while two melanoma cell tissue culture extracts varied in their storage behaviour. One was quite stable at 37° C (losing about 3% of its activity) while the other lost about 16%. Thus both the pig heart t-PA and one t-PA from melanoma cell culture proved suitable for the further development of reference standards for t-PA activity.

Keywords

Tissue plasminogen activator - Stability

• References

• 1 International Committee for Thrombosis and Haemostasis (XXVIIIth Meeting), Fibrinolysis Subcommittee. Bergamo; Italy: 27.07.1982
• 2 Gaffney PJ. Molecular and functional condition of plasma fibrinogen during thrombolytic therapy with streptokinase (SK). Thromb Res 1973; 2: 105-114
• 3 Rijken DC, Collen D. Purification and characterisation of the plasminogen activator secreted by human melanoma cells in culture. J Biol Chem 1981; 256: 7035-7041
• 4 Pennica D, Holmes WE, Kohr WJ, Harkins RN, Vehar GA, Ward CA, Yelverton E, Seeburg PH, Heyneker HL, Goedde DV, Collen D. Cloning and expression of human tissue-type plasminogen activator CDNA in E.Coli. Nature 1983; 301: 214-221
• 5 Hoylaerts M, Rijken DC, Lijnen HR, Collen D. Kinetics of the activation of plasminogen by human tissue plasminogen activator. Role of fibrin J Biol Chem 1982; 257: 2912-2919
• 6 Matsuo O, Rijken DC, Collen D. Thrombolysis by human tissue plasminogen activator and urokinase in rabbits with experimental pulmonary embolism. Nature 1981; 291: 590-591
• 7 Weimar W, Stibbe J, Van Seyen AJ, Billiau A, De Somer P, Collen D. Specific lysis of an ileofemoral thrombus by administration of extrinsic (tissue-type) plasminogen activator. Lancet 1981; 2: 1018-1020
• 8 Collen D, Rijken DC, Van Damme J, Billiau A. Purification of human tissue-type plasminogen activator in centigram quantities from human melanoma cell culture fluid and its conditioning for use in vivo. Thromb Haemostas 1982; 48: 294-296
• 9 Campbell PJ. International biological standards and reference preparations. I. Preparation and presentation of materials to serve as standards and reference preparations. J Biol Stand 1974; 2: 249-258
• 10 Fletcher AP. The measurement of components of the plasminogenplasmin system in biological fluids. Biochem J 1954; 56: 677-682
• 11 Philo RD, Gaffney PJ. Plasmin potency estimates: influence of the substrate used in assay. Thromb Haemostas 1981; 45: 107-109
• 12 Finney DJ. Statistical Method in Biological Assay. 3. Griffin & Co; London: 1978