The large-form urokinasc (L-UK), which has been demonstrated to be more cffcctive in treating thrombosis, was isolated from a crude preparation of local source to electrophoretical homogeneity simply by gel filtration and affinity chromatography. In the isolation of L-UK, a buffer solution of higher ionic strengh (such as 0.1 M phosphate buffer containing 0.1 M or higher NaCl) must be used for eluting the enzyme from a Sephadex gel column. Otherwise, the L-UK may dissociate or degradc to forms of lower molecular weight (e.g. S-UK) with simultaneous polymerization. This is in our opinion, one of the important reasons why variable forms of UK in various ratio were reported previously. In the assay of urokinase activity, the conventional fibrin plate method was modified to be a more reproducible and convenient procedure by punching holes for sample application on an agar-containing fibrin plate.The amino acid as well as sugar compositions and tryptic peptide maps of L-UK were assessed and compared with those of small-form urokinase (S-UK) from Mochida (Japan). It was found that there were great similarities among these enzyme proteins and the homology of L-UK and S-UK in primary structure was proposed.
嘉南學報 9, A48
轉載自 Proc. Natl. Sci. Counc. B. ROC, 7(2), 131-142 (1983)