ASSAY OF PLASMIN AND PLASMINOGEN ACTIVITY IN PLASMA USING A DETERGENTHAVING A LONG ALKYL CHAIN

The inhibitory effect of alpha(2)-plasmin inhibitor (alpha(2)PI) on pl asmin (PLN) was found to be cancelled by a detergent having a long nor mal alkyl chain. Since the detergent did not affect the PLN activity, it should be useful for the determination of plasminogen (PLG) and PLN in plasma that contains a considerable amount of alpha(2)PI. PLN gene ration from PLG by urokinase (UK) was not inhibited by plasma (alpha(2 )PI when cetyltrimethylammonium bromide (C(16)Me(3)Br) was added into the reaction media. C(16)Me(3)Br (0.015%) cancelled the effect of at l east 5 mu g/ml of alpha(2)PI in the sample solution. This concentratio n corresponds to 200 mu g/ml in plasma before dilution and it is about three times the alpha(2)PI level in normal plasma. The standard curve -of the PLG-UK system gave the linearity from 0 to at least 400 mu g/m l of PLG in plasma before dilution. This concentration is as twice the level in normal plasma. Accordingly, plasma PLG can be correctly dete rmined by using this detergent for the reagent.