Abstract
Through the courtesy of Dr. T. E. Weich-selbaum, Washington University, St. Louis, we were supplied with 10 mg of pure crystalline trypsin-inhibitor (1 mg = 4.0 × 10-2 [T.U.]Hb), a polypeptide which was originally isolated from pancreas by Northrop and Kunitz. 1 The sample, dissolved in 10 cc physiological saline, was brought from pH = 5.1 to pH = 7.2 with a trace of n/10 NaOH (= inhib.). The other clotting reagents and test methods have been described in previous publications, 2 the dialyzed crude albumin (= alb.) being prepared from rabbit plasma.
I. Inhibition of clotting of recalcified citrated plasma (rabbit): Whole plasma and several saline dilutions showed unequivocal retardation of clotting on recalcification in the presence of inhib., as compared to controls; e.g., clotting-time of plasma (1:2 dilution) on adding CaCl2: (a) control (with saline) = 3′ 20″; (b) with inhib. = 7′ 05″.
11. Inhibition of thrombic clotting of fibrinogen: −4 1: 100 dilution of Parfentjev's: 1 rabbit clottine globulin (Lederle Lab.) proved an excellent and stable thrombin (T). The following clotting-times (C.T.) were determined at room temperature (21 C) and pH = 7.2, the thrombin, in each case, being mixed with the cited agents for 10 min prior to the addition of the fibrinogen (F):
No. 4 shows a definite antithrombic effect, as compared with the absence of any direct action of the inhibitor, alone, on the thrombin-fibrinogen interaction (No. 2).
Get full access to this article
View all access options for this article.