title: Measurement of antitryptic activity of serum with a centrifugal analyzer.
abstract: The Selected Method [Clin. Chem. 20, 396 (1974)] for the enzymatic assay of alpha1-antitrypsin in serum has been adapted for use with the E.N.I.-GEMSAEC. With alpha-N-benzoyl-D,L-arginine-p-nitroanilide as substrate, the difference between the tryptic activity measured with and without addition of serum in the same run has been used to calculate the trypsin-inhibitory capacity. The rate of increase in absorbance at 400 nm of the p-nitroanilide formed, has been evaluated during a reaction time of 140 s. Results correlated well (r = 0.986) for 54 human sera analyzed as described here and by the Selected Method. The adaptation on GEMSAEC can be used in detecting alpha1-antitrypsin deficiency in the newborn.
mesh_terms: D000328:Adult; D000367:Age Factors; D001322:Autoanalysis; D001586:Benzoylarginine Nitroanilide; D002498:Centrifugation / Q000379:methods; D002648:Child; D003201:Computers; D006801:Humans; D007231:Infant, Newborn; D007700:Kinetics; D014357:Trypsin; D000515:alpha 1-Antitrypsin / Q000032:analysis*
chemical_list: D000515:alpha 1-Antitrypsin; D001586:Benzoylarginine Nitroanilide; D014357:Trypsin