[The inhibition of proteolytic enzyme activity by humic acids]. / Ingibirovanie aktivnosti proteoliticheskikh fermentov guminovymi kislotami.

The inhibitory effect of peat humic acids on the hydrolysis of N-acetyl-L-tyrosine ethyl ester and N-benzoyl-L-leucine methyl ester by alpha-chymotrypsin and subtilism has been studied. Samples of humic acids with M(W) approximately 18,000 have been used in experiments. The results of kinetic studies indicates the mixed type of inhibition of proteinase activity by humic acids. The meanings of inhibition constants under the action of humic acids on alpha-chymotrypsin and subtilism have been calculated.