Gel filtration of tryptic hydrolysates of α-casein

Abstract

The conditions for gel filtration of tryptic hydrolysates of α-casein have been studied. Analysis of the filtrate for absorbancy at 280 mμ, phosphorus, hexose, tryptic activity and reactivity to ninhydrin reagent indicated that the reaction mixture was distributed into characteristic groups of compounds, the most extended separation taking place in acid media. The general differences in filtration characteristics obtained in 1 M acetic acid on 3 dextran gels with different degree of cross-linkages have been demonstrated. Phosphopeptides in the hydrolysate appeared in 4 consecutive groups of compounds on Sephadex G 50, water regain 4.9 g/g dry gel. Trypsin, which is completely excluded from the gel phase of Sephadex G 25, water regain 2.3 g and Sephadex G 50, was distributed into 2 peaks on Sephadex G 75, water regain 8.0 g. Introduction of the gel-filtration method in procedures for preparation of degradation products formed by tryptic hydrolysis of α-casein is discussed.