Automated determination of the antitrypsin activity of serum

An automated determination of the serum antitrypsin activity is described in which all reaction parameters have been optimized. The determination is carried out by measuring the difference between the activity of a standard amount of trypsin with and without addition of serum. Trypsin activity is measured using N-alpha-benzoyl-L-arginine-p-nitroanilide as a substrate. The assay is performed by means of an automatic enzyme reaction rate analyser the Vitatron AKES. The antitrypsin activity is expressed in Inhibitor Units making standardization of the trypsin preparation superfluous. Normal values of the antitrypsin activity for some of the most frequently occurring genetic variants of alpha1-antitrypsin are given.