HEAT STABILITY OF PROTEIN SOLUTIONS OBTAINED FROM HUMAN PLASMA BY DIFFERENT ETHANOL CONCEN- TRATIONS AND TEMPERATURES1

In a previous publication we reported a method for the preparation of a heat stable human plasma protein solution (1). The method was a modifi-cation of that of Cohn, Strong, Hughes, Mulford, Ashworth, Melin, and Taylor (2) and used ethanol-water mixtures at low temperatures for the separation of the heat labile crude fibrinogen fraction (Fraction I) and gamma globulin frac-tion (Fraction II + III) from normal human plasma. The supernatant fluid following the re-moval of the crude gamma globulin fraction was dried from the frozen state and reconstituted to plasma volume with distilled water. Heating of this material for 10 hours at 600 C. changed the optical density at 550 mF and the electrophoretic distribution very little. Electrophoretically, the heated material was 80 per cent albumin, 16 per cent alpha globulin and 4 per cent beta globulin. Heating of the solution for 10 hours at 600 C. caused the formation of a small amount of a very fast moving component in the ultracentrifuge. The remainder representing approximately 90 per cent of the starting protein concentration was homoge-neous and had an uncorrected sedimentation con-stant of approximately 4.0 x 1018.. The present communication concerns the heat stability of human plasma protein solutions re-maining following the precipitation of the Frac-tion II + III proteins from normal human plasma by different ethanol concentrations and tempera-tures