[Effect of various enzyme-substrate ratios on trypsin activity in the presence of trace elements].

In vitro experiments were conducted with trypsin and Na-Benzoyl-l-arginine-p-nitroanilid (L-BAPA) as substrate. The aim of the work was to explore the influence of additional Cu2+, Zn2+, Co2+, Ni2+ and Fe3+ ions in the reaction mixtures on the trypsin activity at different enzyme-substrate ratios (E : S = 1 : 100; 1 : 50; 1 : 10; 1 : 5). The reaction conditions were chosen according to the steady-state conditions of the tryptic hydrolysis.

[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.

Trypsin activity in the small intestine of rats after application of copper and zinc.

In vivo experiments with Sprague-Dawley rats were conducted in order to explore the influence of Cu(2+), Zn(2+) as well as of the combinations of both on the activity of trypsin. The solutions of the trace elements were given per os, the animals were killed 30 min after the applications, and the activity of trypsin was determined in the juice of the small intestine by usingN (α)-benzoyl-L-arginine-p-nitroanilide (L-BAPA) as the substrate. The activity of trypsin depends on the concentration of the trace elements.