PHOSPHOPEPTIDES FROM COMTE CHEESE - NATURE AND ORIGIN

Thirteen low-molecular-weight phosphopeptides were isolated from the w ater-soluble fraction of Comte cheese. The sample was fractionated and purified by gel permeation chromatography and reverse-phase HPLC. The peptide sequences were identified by Edman degradation and primary mo lecular structure was confirmed by mass spectrometry. The different pe ptides purified correspond to fragments of the sequence Val13-Lys 28 o f beta-casein and of the sequence Glu 5-Lys 21 of alpha(s2)-casein. Th ese fragments probably originated from an initial proteolysis of the t wo caseins by plasmin, followed by further endopeptidase aminopeptidas e and, possibly, carboxypeptidase digestions. Partial dephosphorylatio n of some beta-casein fragments was observed. These peptides probably influence the flavor profile of comte cheese.