[Isolation and purification of bovine and porcine cerebral cathepsin D]

Cathepsin D was isolated from the grey matter of bovine and porcine large cerebral hemispheres and purified by affinity chromatography on haemoglobin--Sepharose. The isolation and purification of the enzyme also included: acidic extraction, precipitation by ammonium sulfate, dialysis, affinity chromatography, concentration and gel-chromatography on Sephadex G-100. The degree of purification of bovine cerebral enzyme was 3280. The Km value for the enzyme was 2,06 . 10(-5) M. The purified enzyme from bovine brain showed three major and two minor adjacent bands, possessing the cathepsin D activities. The purified enzyme from porcine brain showed only one protein band.