Action of bacterial collagenase on Ascaris cuticle collagen

The collagen from the cuticle of Ascaris lumbricoides was digested by Clostridium histolyticum collagenase [EC 3.4.24.3] in the presence and absence of CaCl2. About 1.2 mumoles of amino groups per mg collagen was liberated when the digestion was performed in the presence of 5 mM CaCl2, whereas about 0.5 mumole of amino groups per mg collagen was liberated by digestion in the absence of CaCl2. In contrast, CaCl2 influenced the extent of hydrolysis of rat tail tendon collagen only slightly. The results suggest that CaCl2 is necessary for the hydrolysis of certain regions in the molecule of Ascaris collagen and that such structures may not be present in mammalian collagens.