CHEMICAL, CLINICAL, AND IMMUNOLOGICAL STUDIES ON THE PRODUCTS OF HUMAN PLASMA FRACTIONATION. I. THE CHARACTERIZATION OF THE PROTEIN FRACTIONS OF HUMAN PLASMA 12

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Abstract
Plasma was subjected to a large scale fractionation process which yields the different proteins of which it is composed, separated and concentrated. Each concentrate can then be used in therapy in relation to its specialized natural properties and functions. The physical dimensions and properties of the plasma proteins differ widely. All that have been studied, however, have equatorial diams. close to 36 A, a dimension which prevents their rapid loss from the blood stream. The plasma proteins, however, vary in length from 150 A, characteristic of serum albumin, to 900 A, characteristic of fibrinogen. It follows that solns. of the more symmetrical albumin molecules are far less viscous than are those of other plasma proteins. The molecular wts. of the albumins being less than half as great as those of most globulins, their osmotic activity is more than twice as great. Albumins have large numbers of charged groups, symmetrically arranged, and a large net charge which also results in increased osmotic activity. The immune globulins have a smaller net charge, but far greater electric moments, rendering them more reactive with other proteins and electrolytes. The size and shape of the molecules and the nature and structural inter- relations of their free groups determine the physico-chemical characteristics and presumably the physiological functions of the plasma proteins. The plasma proteins differ in their solubility and in their stability in solns. of different pH, temp., dielectric constant, and conc. of dipolar ions, electrolytes or molecules rich in hydroxyl or other groups. The methods of separation that have been developed depend upon these differences in physicochemical properties. The products that have thus far been made available as stable, dry white powders in sufficiently large amts. for clinical appraisal include: (1) fibrinogen, upon which the physical properties of the blood clot largely depend, which can be made into plastics, or in connection with (2) thrombin into (3) fibrin films, used as membranes and (4) into fibrin foams, used as hemostatic agents in neurosurgery; (5) the immune globulins proven of value in measles prophylaxis; (6) the isohemagglutinins in blood typing; and (7) albumin, which represents less than 60% of the plasma protein but is responsible for approx. 80% of the osmotic activity of the blood and is used in the treatment of shock.

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