A Spectrophotometric Method for Measuring Serum Trypsin Inhibitor Capacity

Abstract

The spectrophotometric method of Schwert and Takenaka (11) for the assay of trypsin esterolytic activity has been modified for the measurement of the trypsin inhibitor capacity of serum. An average value of 0.99 mg. of trypsin inhibited per milliliter of serum (3 S.D. = ±0.30) was determined for 50 control subjects. Patient serum assay values determined with this method have been found similar to those determined with the modified Kunitz method using l131-labeled casein as the substrate-in the normal range for a variety of pathologic conditions and in the elevated range for abnormalities of the pancreas and generalized cancer conditions. From the standpoints of accuracy, simplicity, and speed this technic is believed to be an improvement over previous methods for the measurement of this serum variable.