424 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1945 



rated as one and then subjected to subfactionations.) Fraction III-l 

 contains those euglobulin components of plasma, the isoagglutinins, 

 which interact with the red cells according to their specific blood 

 groups and which, therefore, can be used in the typing of blood. 

 Fraction III-l is also rich in certain lipo-proteins containing all the 

 carotenoids and a large part of the cholesterol. Fraction III-2 is 



PLASmA POEinS 



THEIR nATURAL FUnCTIOnS ATlD CLIfllCAL USES 

 AflD SEPARATOR IflTO FRACTION 



Figube 2. — Plasma proteins : their natural functions, clinical uses, and separation 

 into fractions. (Courtesy of Science.) 



largely /^-globulin and contains components important in blood co- 

 agulation, among them thrombin, prothrombin, and a fibrinolytic en- 

 zyme. Fraction IV contains the remaining /J-globulins and most of 

 the a-globulins. Of these a-1 is further separated into Fraction IV-1. 

 Fraction V contains between 85 and 90 percent of the albumin. The 

 mother liquors in Fraction VI contain about 1 percent of the total 



