Kinetics of trypsin from rainbow trout are not influenced by level of feeding.

1. Specific activity and kinetic constants of trypsin from the pyloric caeca of rainbow trout (Salmo gairdneri) were measured. 2. Although one group was fed more than twice as much as the other (1.8 compared to 0.7% body weight per day), there were no significant differences in the weight of the pyloric caeca, specific activity of trypsin, or kinetic constants (apparent Km or Vmax) between the two groups. 3. The caecum of trout contains enough trypsin to digest all of the protein in a typical meal in less than 5 hr.