Localization of Lactic Acid Dehydrogenase Activity in Serum Fractions

Abstract

Using the method of Wroblewski and LaDue the lactic acid dehydrogenase (LDH) activity in serum was localized in 3 electrophoretic regions. In 6 control subjects approximately 48% of the serum LDH activity was present in the alpha2-globulin, 33% between the alphai-globulin and albumin and 19% in the beta-globulin. Three peaks corresponding approximately to those found in serum were observed in the hemolysate from human red cells. In the 2 cases of myocardial infarction in which the total LDH activity was increased, the alphai activity peak was differentially raised while in 3 cases of leukemia, although the total activity was increased in only one instance, the percentage of the total LDH activity in the alpha2 peak was uniformly increased. Results obtained suggest that an examination of the LDH activity in the different serum fractions may provide a more sensitive index of alterations of LDH activity than examination of the total serum concentration of the enzyme.