Influence of Metal Ions on the Activity of Soil Humic-Enzyme Complexes

In the present work, we attempted to elucidate the mechanisms of soil humic acids associations with some proteases. The stability of humic-enzyme complexes and the ways humic acids influence the activity of enzymes were determined. It was shown that humic acids are non-specific inhibitors of proteases. Enzyme-inhibitor complexes are formed by electrostatic, hydrophobic and other types of intermolecular interactions. The protease inhibiting ability of humic acids is influenced by their interaction with metal ions. The stability of enzyme-inhibitor complexes that form by association of proteases with humic-metal complexes depends on the nature of the metals and on the number of coordination centres on the polymeric chains of humic acids.