Physical and chemical properties of the NH2-terminal glutamic acid and lysine forms of human plasminogen and their derived plasmins with an NH2-terminal lysine heavy (A) chain

Kc Robbins,Ig Boreisha,L Arzadon,L Summaria

doi:10.1016/s0021-9258(19)41383-5

Abstract

Comparative physical and chemical data are described for the human NH2-terminal Glu-plasminogen and Lys-plasminogen forms in order to determine the exact relationship between these two types of the zymogen. The molecular weights of Glu-plasminogen and Lys-plasminogen were similar and were determined to be 83, 800 plus or minus 4, 500 and 82, 400 plus or minus 3, 300, respectively, by sedimentation equilibrium methods. The molecular weights were identical in dodecyl sulfate solutions, approximately 83, 000, by sedimentation equilibrium methods. The sedimentation coefficients, s-020, w of Glu-plasminogen and Lys-plasminogen were determined to be 5.0 S, and 4.4 S, respectively. These two plasminogen forms had different partial specific volumes, and calculations of the frictional coefficients from sedimentation coefficients and molecular weights indicated conformation differences. Glu-plasminogen appeared to be larger in size than Lys-plasminogen in acrylamide gel-dodecyl sulfate electrophoresis. The amino acid compositions of Glu-plasminogen and Lys-plasminogen, and their major isolated isoelectric forms, were found to be similar, but several amino acid residues (glutamic acid, alanine, isoleucine, phenylalanine, and lysine) were found to be significantly higher in the Glu-plasminogen forms. The derived plasmins from both the Glu- and Lys-plasminogens with an nh2-terminal Lys- heavy (A) chain were found to have identical molecular weights of 76, 500 plus or minus 2, 500, and sedimentation coefficients, s-020, w of 4.3 S.

Highlights

MethodsPlasminogens and Plasm&s--The Glu-plasminogen forms were prepared from pooled human serum and plasma Fraction III, whereas the Lys-plasminogen forms were prepared from plasma Fraction IIIZ,
Glu-plasminogen and Lys-plasminogen forms in order to determine the exact relationship between these two types of the zymogen
Glu-plasminogen appeared to be larger in size than Lysplasminogen in acrylamide gel-dodecyl sulfate electrophoresis

Summary

Methods

Plasminogens and Plasm&s--The Glu-plasminogen forms were prepared from pooled human serum and plasma Fraction III, whereas the Lys-plasminogen forms were prepared from plasma Fraction IIIZ,. Our modification of the Deutsch and Mertz [9] affinity chromatography method with L-lysine-substituted Sepharose was used to prepare the plasminogens [1]. The zymogens were chromatographed on DEAE-Sephadex followed by gel filtration. 0.05 M Tris-0.02 M lysine-0.10 M NaCI, pH 8.9, by methods previously described [10]. The specific activities of the zymogens were approximately 28 CTA units per mg. Plasmin was prepared from the Glu- and Lgs-plasminogen forms by activation with catalytic amounts of urokinase The isoelectric forms of the Glu- and Lvs-nlasminogens were prepared by methods previously descr

Results

Discussion

Conclusion