Trypsin, chymotrypsin, and total proteolytic activity of pancreas, pancreatic juice, and intestinal contents from the bovine
✍ Scribed by A.D.L. Gorrill; J.W. Thomas
- Publisher
- Elsevier Science
- Year
- 1967
- Tongue
- English
- Weight
- 848 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
Proteolytic
enzyme assays involving the pancreas are dependent on complete extraction and solubilization of the zymogen granules prior to activation. The activation kinetics of purified trypsinogen (Tg) and chymotrypsinogen (ChTg) have been thoroughly studied, and reviewed by Neurath (1) and Northrop et al. (2). However, the optimum activation conditions for a mixture of zymogens in a crude extract of bovine pancreatic homogenate or juice have not been adequately characterized. Activation times ranging from 15 min at 37°C to 24 hr or more at 0 to 5" have been used (3,4). Intestinal contents contain a wide variety of substances that could interfere with enzyme assays. Spectrophotometric esterase assays for trypsin (T) and chymotrypsins A and B (ChT) in rat intestinal contents have been performed (4), but difficulties arose in the present study with one-week-old calves irrespective of diet and older calves fed rations containing soybean protein.
This report compares several procedures for extraction of Tg and ChTg from pancreatic tissue, activation and assay for Tg, ChTg, and total proteolytic activity. Methods employed to remove interfering substances in small intestinal contents, which produced an apparent esterase activity, are presented. MATERIALS AND METHODS (i) Homogenization of Pancreas Pancreatic tissues from calves or cows were cooled on ice and about 0.1 gm samples accurately weighed; 10 ml of ice-cold 0.15 M NaCl or dis-'Published with the approval of the Director of the Michigan Agricultural Experiment Station as Journal Article Number 3910.