Study On Proteomics And Polypeptidomics Of Tissue And Collagen From Camel Hoof

With the rapid aging of the population,collagen series products have been widely concerned by consumers and their market development prospects were broaden.The large collagen family,insufficient raw material development,incomplete functional activity evaluation,insufficient scientific basis and immature industrial production,etc,have been restricting its development.Therefore,it is necessary to seek some new collagen biological raw materials.In this study,camel hoof of Camelus bactrianus as the research object,their nutritional characteristics,differential peptide segments and differential protein expression in three parts of camel hoof,namely,ZJC,ZDC and JMC,were studied based on proteomics and polypeptidomics analysis.The extraction technology and characteristics of camel-derived collagen were analyzed.And the biological functions of collagen peptides which prepared by different enzyme combinations were further studied.(1)The results of conventional ingredients,collagen and amino acids content analy-sis showed that there were tissue differences in camel hoof,and its common nutritional characteristic was that the P/W value was about 0.45.ZDC has high L/P nutritional property,and its amino acid composition was closer to the standard of ideal protein.There was no significant difference in the amino acid composition of the three tissues of camel hoof,and the amino acid composition was similar to that of collagen.Camel hoof could be used as a food protein source of collagen.(2)The identification results of proteomics were that a large number of conserved proteins were retained in the three tissues of camel hoof,including cartilage oligomeric matrix protein,metal binding protein and collagen,etc.Compared with ZJC and JMC,the number of differentially expressed proteins in ZDC was larger,17.8% of total identified proteins.According to the molecular weight and isoelectric point analysis of proteins,it showed that ZDC had more types and contents of large molecular weight proteins.Camel hoof tissues were present weak acidity(PI=6.80).The collagen types in camel hoof tissue were identified to 18 types,mainly type I and type IV,among which type IV collagen was the characteristic collagen,and 16 characteristic peptides were found.KEGG pathway analysis showed that the three tissues of camel hoof obtained unique annotation information from six kinds of biological metabolic pathways,and the signal pathway information had certain similarity.PPI results showed that there were more protein interactions in the glucose metabolism pathway in camel hoof tissues,especially in ZDC,and its indicated that callose pads of camel hoof had special mechanism of heat metabolism.(3)The results of polypeptideomics identification showed that there was a great difference between ZDC,ZJC and JMC,and the number of specific peptides in ZDC was much higher than that in other tissues of camel hoof,accounting for 46.2% of the total number of identified peptides.GO analysis showed that the differential proteins in camel hoof tissues were mainly involved in binding and cell composition.KEGG pathway analysis showed that ZDC was mainly involved in ribosomes of genetic information processing,while JMC and ZJC were mainly involved in cellular processes.It showed that there were differences in protein metabolism among three tissues of camel hoof.PPI results showed that there were many protein interactions in the glycolysis/ gluconeogenesis pathway,among which the protein with high connectivity was GAPDH.And the results were that 71.45% endogenous biological activite peptides in camel hoof,which mainly included ACE inhibitory,DPP-IV inhibitory,antioxidant function and other 14 aspects.The number of active peptides in ZDC was the largest(1871),accounting for 87.6% of the total number of active peptides.And thirty-seven collagen active peptides were identified,mainly from type I,V and VI collagen.(4)Optimization of the response surface was achieved at extraction time of 48 hrs,enzyme dosage of 6.0%,solid-to-liquid ratio of 1:14 and acetic acid concentration of 0.5mol/L.Moreover,the yield of collagen from Bactrian camel hoof achieved good stability and reliability under the above optimal parameter conditions.CAC had all the characteristic absorption peaks of collagen and complete triple helix structure.Proteomic identification revealed seven collagen types and one procollagen enhancer.(5)The results of the preparation of CAC peptides by different enzyme combinations showed that the double enzyme preparation was beneficial to get more CAC peptides.But there was no significant correlation between the yields of CAC peptide and ACE inhibitory ability under different enzymatic hydrolysis methods.The analysis of nutritional characteristics showed that the determination of various amino acids of CAC peptides were higher than that of CAC.The FTIR showed that more proline was exposed in CAC peptides with different enzyme combinations.Identification of polypeptideomics showed that the number and length of the double-enzyme CAC peptide(< 3KDa)were more concentrated,but there had been a marked decrease in numbers.Compared with double-enzyme CAC peptide(< 3KDa),the single-enzyme CAC peptide(< 3KDa)had a wide range of biological activities.It was further suggested that the double-enzyme CAC peptides(< 3KDa)have strong biological activities.