title: Type X collagen contains two cleavage sites for a vertebrate collagenase.
abstract: Type X collagen was cleaved at two sites by a purified human skin collagenase. Two experimental approaches were used to identify the location of the cleavage sites. First, native type X collagen was digested with the enzyme, and the rotary-shadowed products were visualized in the electron microscope. The major collagenase fragment of type X contained the epitope recognized by a monoclonal antibody (X-AC9). The antibody was used as a point of reference to locate the position of the cleavage fragment within the native molecule. Second, the digestion of radiolabeled type X collagen substrates was analyzed by gel electrophoresis. The complete cleavage of type X generated three products with 32-, 18-, and 9-kDa chains. The 32-kDa peptides were present in a triple-helical conformation and demonstrated a midpoint denaturation temperature of 43 degrees C in CD experiments. The 18-kDa peptide contained the tyrosine-rich globular domain of the molecule. The 9-kDa peptide was derived from the triple-helical end of the native molecule. Type X collagen was cleaved more rapidly by the vertebrate collagenase than was type II collagen in in vitro solution studies.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D002642:Chick Embryo; D003094:Collagen / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D046911:Macromolecular Substances; D003012:Microbial Collagenase / Q000378:metabolism*; D008854:Microscopy, Electron; D011489:Protein Denaturation; D012867:Skin / Q000201:enzymology; D013696:Temperature
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D046911:Macromolecular Substances; D003094:Collagen; D003012:Microbial Collagenase