Characterization of a collagenolytic enzyme released from wounded planarians Dugesia japonica

Planarians (Dugesia japonica) were cultured on gels of type I bovine collagen under various conditions that damaged the worms to test the possibility that the animals secrete a collagenolytic enzyme when they are wounded. The planarians were shown to release a potent collagenolytic enzyme around their body when the animals received damage-inducing treatments such as heating at 37 degrees C, freezing and thawing, and amputation. This release of the enzyme did not require the synthesis of RNA or protein. Isolated planarian cells did not release the enzyme even when cultured at 37 degrees C. The collagenolytic activity was found in the supernatants, but not in the insoluble fraction prepared from disintegrated tissues of the wounded animals. These results indicated that the enzyme was stored extracellularly in the normal planarian body. Partial purification of the enzyme and the action spectra of various protease inhibitors on the enzyme showed that the enzyme was a neutral type I collagen-degrading 40 kDa metalloproteinase. We named this enzyme the planarian collagenase.