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A nonantigenic covalent streptokinase-polyethylene glycol complex with plasminogen activator function.

Publication ,  Journal Article
Rajagopalan, S; Gonias, SL; Pizzo, SV
Published in: J Clin Invest
February 1985

A series of new, covalent polyethylene glycol (PEG)-streptokinase adducts were synthesized and characterized. PEGs with average molecular weights of 2,000, 4,000, and 5,000 were activated with carbonyldiimidazole and coupled to the protein under standardized reaction conditions. Steady-state kinetic analysis demonstrated comparable Km values for the activation of plasminogen by streptokinase, PEG-2-streptokinase, and PEG-4-streptokinase. The kcat values were somewhat decreased when PEG-2 or PEG-4 was coupled to the streptokinase. Activation by the PEG-5 adduct did not follow Michaelis-Menten kinetics under the conditions employed in this study. Plasmin activity obtained by incubating streptokinase derivatives with plasminogen also was studied as a function of time with each of the PEG-streptokinase derivatives. By this assay, incubations containing PEG-5-streptokinase and unmodified streptokinase demonstrated comparable activity while reaction mixtures containing PEG-2-streptokinase and PEG-4-streptokinase were slightly more active. Streptokinase incubated with plasminogen at a 1:1 molar ratio was extensively degraded after 30 min whereas PEG-2-streptokinase was resistant to plasmin cleavage. The derivatized proteins were radioiodinated and incubated in plastic microtiter plates that were coated with an immunoglobulin fraction containing antibodies to streptokinase. Binding of the PEG-streptokinase adducts was decreased by greater than 95% compared with unmodified streptokinase. Plasminogen activator complexes were formed by reacting the streptokinases with human plasminogen in vitro and the clearance studied in mice. Radioiodinated plasmin in complex with the PEG-streptokinase adducts cleared at a slower rate than did plasmin complexed with unmodified streptokinase. Catabolism of the protease still occurred by a mechanism that involved reaction with alpha 2-macroglobulin as has been described for nonderivatized streptokinase-plasminogen complex (Gonias, S. L., M. Einarsson, and S. V. Pizzo, 1982, J. Clin. Invest., 70:412-423). When more extensive derivatization procedures were utilized, PEG-2-streptokinase preparations were obtained that further prolonged the clearance of complexed 125I-plasmin; however, these adducts did not uniformly retain comparable activity. It is suggested that PEG-streptokinase complexes with greatly reduced antigenicity may be useful in the treatment of thrombotic disorders.

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Published In

J Clin Invest

DOI

ISSN

0021-9738

Publication Date

February 1985

Volume

75

Issue

2

Start / End Page

413 / 419

Location

United States

Related Subject Headings

  • Streptokinase
  • Polyethylene Glycols
  • Plasminogen Activators
  • Plasminogen
  • Mice
  • Metabolic Clearance Rate
  • Kinetics
  • In Vitro Techniques
  • Immunology
  • Fibrinolysin
 

Citation

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Rajagopalan, S., Gonias, S. L., & Pizzo, S. V. (1985). A nonantigenic covalent streptokinase-polyethylene glycol complex with plasminogen activator function. J Clin Invest, 75(2), 413–419. https://doi.org/10.1172/JCI111715
Rajagopalan, S., S. L. Gonias, and S. V. Pizzo. “A nonantigenic covalent streptokinase-polyethylene glycol complex with plasminogen activator function.J Clin Invest 75, no. 2 (February 1985): 413–19. https://doi.org/10.1172/JCI111715.
Rajagopalan S, Gonias SL, Pizzo SV. A nonantigenic covalent streptokinase-polyethylene glycol complex with plasminogen activator function. J Clin Invest. 1985 Feb;75(2):413–9.
Rajagopalan, S., et al. “A nonantigenic covalent streptokinase-polyethylene glycol complex with plasminogen activator function.J Clin Invest, vol. 75, no. 2, Feb. 1985, pp. 413–19. Pubmed, doi:10.1172/JCI111715.
Rajagopalan S, Gonias SL, Pizzo SV. A nonantigenic covalent streptokinase-polyethylene glycol complex with plasminogen activator function. J Clin Invest. 1985 Feb;75(2):413–419.

Published In

J Clin Invest

DOI

ISSN

0021-9738

Publication Date

February 1985

Volume

75

Issue

2

Start / End Page

413 / 419

Location

United States

Related Subject Headings

  • Streptokinase
  • Polyethylene Glycols
  • Plasminogen Activators
  • Plasminogen
  • Mice
  • Metabolic Clearance Rate
  • Kinetics
  • In Vitro Techniques
  • Immunology
  • Fibrinolysin