Action of Rennin on κ-Casein

Abstract

The action of rennin on κ-casein was studied as a function of time using several methods to measure activity. The first indication of rennin cleavage of κ-casein is precipitability in .1 M acetate buffer at pH 5.2 and 5 C. A longer exposure to rennin is required to alter κ-casein so that it forms a precipitate with calcium ions and loses its ability to stabilize αs-casein. The least sensitive indication of rennin activity is measurement of nitrogen soluble in 2% trichloroacetic acid. Electrophoresis experiments showed that these methods detect various stages in the conversion of κ-casein to para-κ-casein. © 1975, American Dairy Science Association. All rights reserved.