A NEW METHOD TO ESTIMATE CASEINOMACROPEPTIDE AND GLYCOMACROPEPTIDE FROM TRICHLOROACETIC-ACID FILTRATES

A new approach to estimate caseinomacropeptide (CMP) as well as its gl ycosylated part (GMP) was developed using rennet whey and two caseins as substrates. The assay is based on a controlled solubilization of CM P and GMP at trichloroacetic acid (TCA) concentrations of 6% and 12%, respectively, followed by a desalting step on Econo Pak 10 DG. The res ulting eluates were measured spectrophotometrically at 217 nm using 1 cm cuvettes. Calibration was carried out by renneting pure kappa-casei n and analyzing the TCA filtrate according to the new procedure. The s pectrophotometric results were compared with chromatographic findings obtained by FPLC and a Mono S column. It was shown that (a) the spectr ophotometric method does correlate with the peak areas of the chromato graphic separations for CMP and (b) both procedures, the use of 6% TCA in presence of 0.175 M Na2SO4 as well as the isoelectric precipitatio n, are well comparing in their efficiency to solubilize CMP.