Activators: Ca²⁺ is required. Inhibitors: Metal chelating agents such as cysteine, EDTA or o-phenanthroline but not DFP. It is also inhibited by a2-macroglobulin - a large plasma glycoprotein. The human skin enzyme is inhibited by human serum but granulocyte collagenase is not. Human serum contains a2-macroglobulin and a1-antitrypsin that may inhibit certain collagenases.

• One unit equals one micromole of L-leucine equivalents from collagen in 5 hours at 37 °C and pH 7,5 under the specified conditions.

Collagenase Type IV has low tryptic activity. It is commonly used for islets and other applications where receptor integrity is crucial.

The material has been tested for caseinase, clostripain and tryptic activities.