Collagenase in the Walker 256 Carcinoma. A Study of the Latent and Active Enzyme in vivo and in vitro

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Abstract
A latent form of collagenase was isolated from crude extracts of the insoluble, fibrous material from [rat] Walker tumor homogenates. Purified preparations of this enzyme yielded a major unit of MW .apprx. 62,000, as determined by gel filtration on AcA 54 Ultrogel. In its activated form collagenase was purified to apparent homogeneity with an .apprx. MW of 42,000. The active enzyme cleaved soluble collagen into three-quarter and one-quarter length fragments in the manner of vertebrate collagenases. Latent collagenase from culture media eluted with an apparent MW of 53,000 and was slightly larger in size than its activated form that eluted at 42,000. Extracted latent collagenase and latent collagenase from culture media could be activated enzymatically by trypsin or chymotrypsin and non-enzymatically by mersalyl, an organic mercurial compound. Latent collagenase from Walker tumors may be complexes of active enzyme with inhibitor(s) of low MW and are not true zymogens.