The purification and properties of human plasminogen

Abstract

Two methods for the purification of human plasminogen from the euglobulin fraction of serum or from Cohn human-plasma fraction HI, differing essentially by the use of [epsilon] -aminohexanoic acid in one but not in the other procedure, have been described. Both preparations were of specific activity comparable with that of plasminogen prepared by acid-purification procedures, but differed from these latter preparations with respect to their stability and solubility at neutral pH. Biophysical examination of these preparations, acid-purified plasminogen (A) and plasminogen of both types (A and B) in the presence of [epsilon] -aminohexanoic acid, revealed that, according to its method of preparation and treatment, plasminogen might exhibit 1 of 3 types of ultracentrifugal or 1 of 2 types of electrophoretic behavior. Interconversion of these plasminogen,types, by appropriate treatment of the preparations, was demonstrated, and it was concluded that the plasminogen molecule exhibits unusual plasticity, differences in various preparation properties being related to wholly or partially reversible structural changes.