umls-concept:C0007427 | skos:definition | MSH: An intracellular proteinase found in a variety of tissue. It has specificity similar to but narrower than that of pepsin A. The enzyme is involved in catabolism of cartilage and connective tissue. EC 3.4.23.5. (Formerly EC 3.4.4.23).,NCI: Cathepsin D, encoded by the CTSD Gene, is a lysosomal aspartyl protease composed of a dimer of disulfide-linked heavy and light chains, both produced from a single protein precursor. It has a specificity similar to but narrower than that of pepsin A, decomposing cytoplasmic proteins, cell organelles, collagen, elastase and proteoglycans. Cathepsin D takes part in angiogenesis and activates osteoclasts, and plays a major role in the destruction of bone tissue by cholesteatoma. Transcription of the CTSD gene is initiated from several sites, including one which is a start site for an estrogen-regulated transcript. Mutations in this gene are involved in the pathogenesis of several diseases, including breast and ovarian cancer, and possibly Alzheimer disease. (From LocusLink | lld:umls |