Hypothalamic cathepsin D: Assay and isoenzyme composition

✍ Scribed by T. N. Akopyan; N. A. Barchudaryan; L. V. Karabashyan; A. A. Arutunyan; A. Lajtha; A. A. Galoyan

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 310 KB
• Volume: 4
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490040505

✦ Synopsis

I NTROD UCTl ON

Cathepsin D, one of the main intr-acellular proteinases. plays an important role in the breakdown of proteins in normal cells [ l , 21 and also in thc pathologic processes of tissue breakdown [3,4]. Although the successful purification of this enzyme has been reported from different sources [5-9] , data concerning the isoenzyme composition of this enzyme are lacking.

Previously, we reported thc purification and some properties of acid proteinase from bovine hypothalamus, including its action o n somatostatin and substance P [ l o ] . This enzyme was identified by us as cathepsin D (EC 3.4.2.3). During purification of calhepsin D from hypothalamus we observed multiple peaks of enzyme activity. This observation was extended t o study the isoenzyme composition of cathepsin D in hypothalamus. and powerful method. A difficulty of this method is that fractions from focusing columns contain ampholines and sucrose, which interfere with those methods of measuring proteinase activity that utilize amino group and tyrosinc-detecting reagents.

for endopeptidase assay and the use of this method for determination of acid proteinases of bovine hypothalamus separated by an isoelectric focusing column.

For resolution of enzymes having similar activities, isoelectric focusing is a suitable In this communication, we report the development of a simple and sensitive method Address reprint requests to T.