Identification of Marker Peptides in Digested Gelatins by High Performance Liquid Chromatography/Mass Spectrometry

Sequence analysis of bovine and porcine collagen type I indicated that some partial sequences are specific for bovine or porcine collagen type I, which could be used as marker peptides for gelatin differentiation. Bovine and porcine gelatins were digested with trypsin. The digested mixtures were analyzed with high-performance liquid chromatography/mass spectrometry (HPLC/MS). Marker peptides were identified by peptide sequence tag method. The results indicated that the bovine and porcine gelatins could be differentiated according to the sequences of marker peptides. Further analysis indicated that some prolines in the marker peptides were hydroxylated, which should be taken into account to increase the confidence in peptide identification. The relative abundance of marker peptides in gelatins with different molecular weight ranges was also investigated. The results indicated that identification of the marker peptides in the digested gelatins by HPLC/MS is a feasible method for differentiation of bovine and porcine gelatins.