Abstract
It has been shown that lignosulphonic acids have an inhibitory effect on various animal and microbial proteinases. The activity of 0.005 mg swine trypsin, 0.007 mg bovine a-chymotrypsin and the proteinase activity in 0.004 ml of jejunum content from pig is inhibited 70–75 % by 0.25–0.30 ml of a solution containing 250 diffusion units of peptide-precipitating lignosulphonic acids per 50 µl. The inhibitory effect is discussed in relation to the use of animal foodstuffs containing lignosulphonic acids, and in relation to biochemical reactions taking place in ecosystems in which lignosulphonic acids comprise an important part.