Quinetides: diverse posttranslational modified peptides of ribonuclease-like storage protein from as markers for differentiating ginseng species.

BACKGROUND

Peptides have diverse and important physiological roles in plants and are ideal markers for species identification. It is unclear whether there are specific peptides in L. (PQ). The aims of this study were to identify Quinetides, a series of diverse posttranslational modified native peptides of the ribonuclease-like storage protein (ginseng major protein), from PQ to explore novel peptide markers and develop a new method to distinguish PQ from

METHODS

We used different fragmentation modes in the LTQ Orbitrap analysis to identify the enriched Quinetide targets of PQ, and we discovered Quinetide markers of PQ and using ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry analysis. These "peptide markers" were validated by simultaneously monitoring Rf and F11 as standard ginsenosides.

RESULTS

We discovered 100 Quinetides of PQ with various post-translational modifications (PTMs), including a series of glycopeptides, all of which originated from the protein ginseng major protein. We effectively distinguished PQ from using new "peptide markers." Four unique peptides (Quinetides TP6 and TP7 as markers of PQ and Quinetides TP8 and TP9 as markers of ) and their associated glycosylation products were discovered in PQ and .

CONCLUSION

We provide specific information on PQ peptides and propose the clinical application of peptide markers to distinguish PQ from .