The estimation of tryptic activity in duodenal contents

Abstract

4 g. of dehydrated human serum is dissolved in 100 ml. of 0.01 [image] NaOH and denatured at 100[degree] for 12 min.; after filtering, 1/4 vol. of [image] NH4Cl-NH4OH, pH 9.5, is added. Human duodenal juice is obtained by intubation and mixed immediately with an equal vol. of glycerol. 2.5 ml. of the juice-glycerol is added to 5.0 ml. of substrate-buffer above and incubated at 37[degree] for exactly 15 min., when 10 ml. of 0.35 [image] trichloroacatic acid is added. After filtering, 2 ml. is added to 20 ml. of 0.25 [image] NaOH and 1 ml. of Folin-Ciocalteau''s phenol reagent, and after 15 min. the blue color is measured photocolor-imetrically. One unit of enzyme activity produces a chromogenic activity equivalent to 1 ml./l. of phenol. Results by this method show good correlation with those by the Lagerlof procedure (Acta Med. Scand. Supple. 128. 1942). Ranges of activity for juice (66% of values) were resting, 8-38; after secretion, 25-75; and after pancreozymin, 50-80 units/ml.