Some observations on the affinity chromatography of rabbit plasminogen

The feasibility of isolating plasminogen allomers from plasma by affinity chromatography in a single stage and the specificity of Sepharose-lysine for plasminogen are examined.It is shown that the method of Castellino can readily be adapted by relatively minor modifications as a one-stage procedure without endangering the quality of the product. The optimal degree of lysine conjugation with Sepharose is defined for this process.Experiments with labelled allomers are described showing the competitive nature of the capture of plasminogen by Sepharose-lysine. The affinity behaviour of plasmin and of complexes of plasmin with serum protease inhibitors are compared to plasminogen. Several other plasma proteins which also exhibit affinity to lysyl groups are identified.Plasminogen obtained in the present study compares well with previously reported analyses for molecular weight, N-terminal amino acid and sialic acid content, but not for neutral carbohydrates.