Discovery of species-specific peptide markers and development of quality-evaluation strategies for deer horn gelatin using liquid chromatography-tandem mass spectrometry and a label-free methodology.

Deer horn gelatin (DHG) is a valuable nutritional dietary supplement. Due to the significant variation in the price of DHG from different sources, it is important to assess its quality and to clarify the species of its raw material. However, due to the similarity in appearance and physicochemical properties, as well as the destruction of genetic material during the manufacturing process, it is difficult to distinguish DHG from gelatin derived from other sources. Furthermore, current methods are unable to evaluate the overall quality of DHG. Using Nano LC-Orbitrap MS and data analysis software, DHG samples from five deer species were analyzed to identify peptide markers specific to alpha-2-HS-glycoprotein (AHSG) and collagen. The peptide markers were validated using HPLC-Triple Quadrupole MS, and strategies for assessing the quality of DHG were developed. Eighteen peptide markers were discovered, comprising peptides with differing specificities. Three strategies for the identification, characteristic mapping, and content determination of DHG were developed. These strategies can be used to assess the quality of deer gelatin.

[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.

Discovery of peptide biomarkers by label-free peptidomics for discrimination of horn gelatin and hide gelatin from Cervus nippon Temminck.

Gelatin and gelatin-based derivatives have been attracting worldwide attention as health-food ingredients. Deer horn gelatin (DCG), a well-known and expensive gelatin food in Asia, has suffered adulterants by adding deer-hide gelatin (DHG) in it. However, robust and effective methods which could differentiate DCG from DHG are still unavailable. This study is committed to discover peptide biomarkers to distinguish DCG from DHG using label-free peptidomics by nanoLC-MS/MS. Multivariate statistical analysis combined with glycosylation sites analysis of peptides was applied to visualize the difference between DCG and DHG. As a result, four peptide biomarkers for distinguishing DCG and DHG were confirmed and validated by UPLC-MS/MS and MRM mode, which was also used to calculate adulteration percentage in commercial samples. The presented strategy may be also particularly helpful in the in-depth authentication of food gelatins from different tissues of the same species.