[Effect of Cu++ ions on the activity of trypsin on natural substance]

In vitro experiments were carried out in order to investigate the influence of Cu++-ions on the tryptic hydrolysis of casein and soybean protein. The admixture of 10(-3) to 10(-2) Mol Cu++/l to the reaction preparations results in the activation of trypsin in both substrates. The further increase of the Cu++-concentration results in a decrease of the trypsin activity and, with casein as substrate, in trypsin inhibition. The effects are similar with the synthetic substrate N alpha-benzoyl-L-arginine-p-nitroamilide (L-BAPA), however, trypsin is already activated after the admixture of approximately 5 x 10(-6) Mol Cu++/l. Since the admixture of Cu++-ions in experiments with pepsin in similar concentrations as with trypsin also results in an activation, the question is being discussed whether the improved protein digestibility and the higher weight increase of pigs which received 250 ppm copper can be traced back to these effects.