APPLICATION OF A MASS-SPECTROMETRY SEQUENCING TECHNIQUE FOR IDENTIFYING PEPTIDES PRESENT IN CHEDDAR CHEESE

Peptides were isolated from a water-soluble fraction of a commercial m ature Cheddar cheese by reversed phase-high performance liquid chromat ography. Character isation of 16 peptides was performed using a matrix assisted laser desorption/ionisation time-of-flight mass spectrometer , by determining their masses and applying N-terminal sequencing using a volatile degradation reagent, trifluoroethylisothiocyante. The expe rimental approach allowed the sequencing of overlapping peptide mixtur es. Of the 16 peptides identified, eight came from alpha(s1)-casein, s even from beta-casein and one from alpha(s2)-casein. Copyright (C) 199 6 Elsevier Science Limited