[Cathepsins D from normal and some human neoplasms]

Cathepsins D were isolated from human liver and spleen, from three malignant tumours (kidney cancer, sarcoma, spleen tumour caused by chronic myeloleucosis) and from one non-malignant tumour (uterine myoma). The isolation procedure involved adsorption on pepstatin-Sepharose and gel-filtration on Sephadex G-100. A comparative study of the properties of these enzymes was carried out. The molecular weights, specific proteolytic activity toward hemoglobin and the synthetic hexapeptide Acetyl-Val-Val-Leu-Ser-Leu-Thr, carbohydrate content and type of dissociation of the molecules into polypeptide fragments during electrophoresis in the presence of DS-Na were determined. All the enzymes under study had molecular weights of about 45 000 except uterine myoma cathepsins (mol. weight 95 000). The latter cathepsin also differed from the other enzymes in its higher carbohydrate content.