[Measurement of alpha 2-macroglobulin in human sera by quantitative inhibition of an acid staphylococcal protease (author's transl)].

Concentrations of alpha 2-macroglobulin could be determined in the sera of 215 blood donors and 94 patients with various internal diseases by quantitative inhibition of an acid protease from Staphylococcus aureus, M 135 (fig. 1, 2). The determinations agreed closely with those obtained by immunodiffusion (tab. 1, fig. 3). However, the alpha 2-macroglobulin-measurements by the protease method required only 4 h and 40 microliter serum. This procedure would also be suitable for the determination of alpha 2-macroglobulin in sera from experimental and domestic animals.