Method of inhibiting cathepsin K

A method of identifying an inhibitor compound capable of binding to, and inhibiting the proteolytic activity of, cathepsin K, said method comprising:

• introducing the protein coordinates of Table I into a suitable computer program so as to define an active site conformation of a cathepsin K molecule comprising an active site formed by the residues listed in Table XXIX, said active site defined by the protein coordinates of Table I, wherein said program displays the three- dimensional structure of the active site;
• creating a three dimensional representation of the active site in said computer program;
• displaying and superimposing a three dimensional representation of a test compound on the three dimensional representation of the active site;
• assessing whether said test compound fits spatially into the active site;
• preparing said test compound that fits spatially into the active site;
• using said test compound in a biological assay for a protease characterized by said active site;
• and
• determining whether said test compound inhibits cathepsin K activity in said assay.