RAPID PROCEDURE FOR ISOLATING THE BITTER CARBOXYL-TERMINAL FRAGMENT 193-209 OF BETA-CASEIN ON A PREPARATIVE-SCALE

A rapid procedure for isolating the carboxyl-terminal fragment 193-209 of beta-casein, the bitter C-peptide, on a preparative scale is descr ibed. The C-peptide was preferentially cleaved from beta-casein by chy mosin and subsequently purified by ultrafiltration after acid precipit ation of residual large beta-casein fragments. Although the C-peptide was strongly hydrophobic, it acted in a hydrophilic way, showing littl e interaction with other hydrophobic parts of beta-casein. Ultrafiltra tion and dialysis experiments showed that the peptide was probably oli gomeric in aqueous solutions, with oligomers in equilibrium with lower -molecular-mass species.