The Streptokinase Activation of Human Plasminogen. Direct Analysis of the Activation Mixture

Summary

1. Incubated mixtures of plasminogen and streptokinase revealed three components in optical electrophoresis at pH 2.00. The fastest component was identified as plasmin, and the other two components were taken to represent plasminopeptides A and B, in accordance with their mobilities.

2. By means of gel filtration, it was possible to show the presence of three constituents. The major one had caseinolytic activity, while the other two had no such activity.

3. From the known properties of molecular exclusion by various Sephadex preparations, it was estimated that the two peptides had molecular weights of approximately 10,000.

4. The possibility of improving the purity of plasmin preparations was demonstrated.

^* Present address: Universidad Nacional de Cordoba, Instituto de Biología Celular, Cordoba, Argentina.

^** Recipient of a Research Career Development Award (GM-K3-1377) from the U. S Public Health Service.

• References

• 1 Sherry S, Fletcher A. P, Alkjaersig N. Fibrinolysis and Fibrinolytic Activity in Man. Physiol. Rev. 39: 343 1959;
• 2 Rifé U, Shulman S. Molecular Changes in Activation of Plasminogen. Fed. Proc. 19: 59 1960;
• 3 Shulman S, Rife U. Abstracts. First Internat. Biophysics Congr. 145. 1961
• 4 Shulman S, Rife U. Preliminary Studies on the N-Terminal Amino Acids of Human Plasminogen. Thrombos. Diathes. haemorrh. (Stuttg). 05: 396 1961;
• 5 Shulman S, Rife U. Molecular Changes in the Activation of Plasminogen. I. The Release of Peptide Fragments. Biochim. biophys. Acta (Amst.) submitted. 1963
• 6 Kline D. L. The Purification and Crystallization of Plasminogen (Profibrinolysin). J. biol. Chem. 204: 949 1953;
• 7 Remmert L. F, Cohen P. P. Partial Purification and Properties of a Proteolytic Enzyme of Human Serum. J. biol. Chem. 181: 431 1949;
• 8 Shulman S, Alkjaersig N, Sherry S. Physicochemical Studies on Human Plasminogen (Profibrinolysin) and Plasmin (Fibrinolysin). J. biol. Chem. 233: 91 1958;
• 9 Porath J, Flodin P. Gel Filtration: A Method for Desalting and Group Separation. Nature. 183: 1657 1959;
• 10 Shulman S. Purification and Identification of Components of Human Plasminogen Preparations. Biochim. biophys. Acta (Amst). 46: 6 1961;
• 11 Pharmacia (Uppsala). Sephadex in Gel Filtration.. 1961
• 12 Polson A. Fractionation of Protein Mixtures on Columns of Granulated Sugar. Biochim. biophys. Acta (Amst). 50: 565 1961;
• 13 Porath J. Gel Filtration of Proteins, Peptides and Amino Acids. Biochim. biophys. Acta (Amst). 39: 193 1960;
• 14 Porath J, Lindner E. B. Separation Methods based on Molecular Sieving and Ion Exclusion. Nature. 191: 69 1961;
• 15 Cortis-Jones B. ^cGel Filtration⁵ of Organic Compounds. Nature. 191: 272 1961;
• 16 Granath K. A, Flodin P. Fractionation of Dextran by the Gel Filtration Method. Makromol. Chem. 48: 160 1961;
• 17 Glazer A. N, Wellner D. Adsorption of Proteins of ‘Sephadex’. Nature. 194: 862 1962;