Collagenase is a protease consisting of a single polypeptide chain approximately 1,000 amino acid residues in length. Collagenase is capable of digesting native collagen fibrils commonly found in connective tissues and therefore is frequently used for tissue dissociation. Collagenase preparations contain the activity of several proteases, including collagenase, caseinase, clostripain, and trypsin (Kessler & Yaron). Collagenase Type II contains high levels of protease activity, especially clostripain, and has been used for the digestion of lung (You & Brody; Comhair et al.), kidney (Valente et al.), liver (Linghor et al.), thymus (Vandenabeele et al.), endothelial cells (Patel et al.) and mesenchymal stem cells (Steigman & Fauza).