[Label-free quantitative peptidomics-based analysis on glycopeptides in deerhorn gelatin and deer-hide gelatin]

Nano-LC-MS/MS was used to analyze trypsin digested deer-horn gelatin( DCG) and deer-hide gelatin( DHG) samples.The glycopeptides in DCG and DHG were quantified by Label-free quantitative( LFQ) peptidomics,on the basis of which the glycopeptides with significant difference in DCG and DHG were determined. As a result,5 736 peptides were identified from DCG samples,including 213 galactosyl-hydroxylysine containing peptides( Gal-Hyl-peptides) and 102 glucosyl-galactosyl-hydroxylysine containing peptides( Glc-Gal-Hyl-peptides),while 6 836 peptides were identified from DHG samples,among which there were 250 Gal-Hyl-peptides and 98 Glc-Gal-Hyl-peptides. With over 3-fold peak area difference and highly significant intergroup difference( P < 0. 01) as the screening criteria,444 differential peptides were determined in DCG and DHG,including 16 Gal-Hyl-peptides and 5 Glc-Gal-Hyl-peptides. Then XIC peak shapes,standard deviation of peak area,and fold change were applied for further screening and 5 glycopeptides with significant differences in DCG and DHG were confirmed,which could serve as potential biomarkers for distinguishing DCG and DHG. The present study provided ideas and strategies for the in-depth investigation on the discrimination of DCG and DHG and is of good theoretical significance and application value for the further research on chemical constituents and quality control of gelatin derived Chinese medicinals.