Purification of bovine spleen collagenolytic cathepsin, (cathepsin N).

Purification of Bovine Spleen Collagenolytic Cathepsin (Cathepsin N) ANDRE DUCASTAING* and DAVID J. ETHERINGTON Agricultural Research Council, Meat Research Institute, Langford, Bristol BS18 I D Y , U.K. The lysosomai enzymes cathepsin B and collagenolytic cathepsin are believed to have a physiological role in the turnover and resorption of collagen (Etherington, 1977). Collagenolytic cathepsin has been purified from human placental tissue (Evans & Etherington, 1978), but in previous studies of the bovine enzyme only a partially purified preparation was available. A method has now been developed for the purification of bovine collagenolytic cathepsin of high specific activity and with a good recovery. The enzyme becomes unstable during the later stages of purification, which had frustrated these earlier attempts to obtain pure enzyme. The present method is shown schematically in Fig. 1 . * Present address: Laboratoire de Biochirnie de la Nutrition, Universite de Bordeaux I, Avenue des Facultes, 33405 Talence Cedex, France.