Comparative proteomics of whey proteins: New insights into quantitative differences between bovine, goat and camel species

Novel insights into differences in the whey proteome of porcine and human colostrum and mature milk

Many mothers are unable to exclusively breastfeed for several reasons. Other mammalian milks should be explored as human milk supplements. Pigs and humans are physiologically similar. Therefore, we hypothesized that the whey protein composition and functions of porcine and human milk are similar. This study aimed to compare and analyze the whey proteomes of porcine and human milk during lactation. Totally, 3390, 3275, 3587, and 3463 whey proteins were identified in porcine colostrum, porcine mature milk, human colostrum, and human mature milk, respectively. Complement components and serotransferrin, which are related to the immune system process were highly expressed in porcine milk. Porcine and human whey proteins were enriched in similar Gene Ontology annotations and Kyoto Encyclopedia of Genes and Genomes pathways. These results revealed that the biological functions of porcine and human whey proteins were similar, which contributes to the development of porcine whey proteins.

Human milk whey proteins: Constituents, influencing factors, detection methods, and comparative analysis with other sources

Whey proteins, the most abundant proteins in human milk (HM), play a vital role in the growth and development of infants. This review first elaborates on the main components of HM whey proteins, including various proteins with specific functions, and details the functions of these proteins in terms of infant nutrition, immunity, as well as growth and development. Secondly, it analyzes factors that affect HM whey proteins, such as maternal differences, dietary habits, and geographical differences. Thirdly, it discusses detection methods for HM whey proteins, covering the principles, advantages, and limitations of different technical means. Finally, it compares whey proteins from different milk sources, highlighting their differences in composition, function, and characteristics. This review aims to comprehensively present the current research status of HM whey protein, provide a scientific basis for maternal and infant health, and contribute to optimizing infant feeding strategies and the research and development of related products.

Insights into the microscopic heterogeneity of whey proteins between yak colostrum and mature milk based on 4D lable-free quantitative phosphoproteomics

This study aimed to reveal the change patterns of the phosphorylation modification status of yak whey phosphoproteins during lactation and their physiological effects. Herein, we comprehensively characterized whey phosphoproteome in yak colostrum and mature milk using an ultra-high throughput phosphoproteomics approach incorporating trapped ion mobility technology. A total of 344 phosphorylation sites from 206 phosphoproteins were identified, with individual site modification predominating. Notably, 117 significantly different phosphorylation sites were distributed on 89 whey phosphoproteins. Gene ontology analysis indicated that these significantly different whey phosphoproteins (SDWPPs) were mainly annotated to carbohydrate metabolic process, membrane, extracellular region and calcium ion binding. Metabolic pathway enrichment analysis demonstrated that SDWPPs were critically involved in protein processing in endoplasmic reticulum, NOD-like receptor signaling pathway and N-glycan biosynthesis. Our results elucidate the phosphorylation profiles of yak whey phosphoproteins at different lactations and their adaptive regulatory role in meeting the nutritional requirements of yak calves during development.

Spectroscopic and Molecular Docking Studies on the Influence of Inulin on the Interaction of Sophoricoside with Whey Protein Concentrate

The influence of inulin on the interaction of sophoricoside (Sop) with whey protein concentrate (WPC) was investigated using various spectroscopic methods, including fluorescence spectroscopy (intrinsic fluorescence, synchronous fluorescence, and three-dimensional fluorescence), ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and molecular docking. Sop was found to quench the intrinsic fluorescence of WPC by a static mechanism, both with and without the addition of inulin, and to enhance the antioxidant capacity of the protein. The addition of inulin slightly increased the binding distance between WPC and Sop, while reducing the number of binding sites from two to one. Non-covalent interactions, predominantly van der Waals forces and hydrogen bonding, were maintained between Sop and the protein. Synchronous fluorescence spectroscopy revealed that Sop prevents the exposure of hydrophobic groups on tryptophan residues, leading to increased surface hydrophilicity of the WPC complex. This aligns with the decreased protein surface hydrophobicity measured by 8-Anilino-1-naphthalenesulfonic acid (ANS) binding assays. With inulin, the overall hydrophobicity of the protein was lower than in the system without inulin, suggesting that both inulin and Sop improve the solubility of WPC. Three-dimensional fluorescence spectral analysis showed a reduction in fluorescence intensity and a red shift in the presence of both Sop and inulin. FTIR spectroscopy indicated a slight increase in the secondary structure ordering of WPC following the addition of both Sop and inulin, suggesting structural stabilization under heating conditions. Molecular docking highlighted the potential for hydrogen bond formation between Sop and WPC.

Comparison of Whey N-Glycoproteins in Yak Colostrum and Mature Milk Based on 4D Label-Free Technology

Whey proteins are N-glycosylated proteins that play important roles in a variety of biological processes including immune defense. However, the N-glycosylation of yak colostrum (YC) and mature milk (YM) whey proteins is unknown. Therefore, this study systematically compared and analyzed YC and YM whey N-glycoproteomes using the 4D label-free technique. We identified 162 glycoproteins, 222 glycosylated peptides, and 234 glycosylation sites in YC and YM, of which 59 glycoproteins were differentially expressed in YC and YM. According to gene ontology annotation and KEGG pathway metabolism analysis, the differentially expressed N-glycoproteins were highly enriched in "cell adhesion", "extracellular region", and "calcium binding", and were mainly involved in the extracellular matrix (ECM)-receptor interaction pathway. The immunity-related N-glycoproteins, such as platelet glycoprotein 4 (CD36) and polymeric immunoglobulin receptor (PIGR), were observed to be different between YC and YM. The results revealed the glycosylation sites, composition, and biological functions of YC and YM whey N-glycoprotein, which supplemented our understanding of the N-glycosylation of yak whey proteins.

Novel insights into whey protein among Yak, Yellow Cattle, and Cattle-Yak milk

This study identified characteristic whey proteins from Zhongdian Yak (ZY), Diqing Yellow Cattle (DYC), and Cattle Yak (CY), revealing insights into their potential functions and released peptides. A total of 118 whey proteins were quantified in milk obtained from the three breeds of cattle, including seven characteristic proteins (IGL@ protein, 40S ribosomal protein S9, calreticulin, etc.) in CY milk and two characteristic proteins (RNA helicase and uncharacterized protein (A0A3Q1LFQ2)) in ZY milk. These characteristic proteins are involved in the phagosome and Fc gamma R-mediated phagocytosis pathways, exhibiting immunoprotective activities, verified through molecular docking. Furthermore, the molecular docking results showed five whey proteins (IGL@ protein, rho GDP-dissociation inhibitor 1, small monomeric GTPase, action-like protein 3, and adenylyl cyclase-associated protein) interacted with TLR4 through multiple hydrogen and hydrophobic bonds. Therefore, these proteins may exert immunomodulatory functions by inhibiting TLR4. Meanwhile, whey proteins produced bioactive peptides, such as antioxidant peptides and ACE inhibitory peptides after simulated gastrointestinal digestion (SGID). The whey proteins and bioactive peptides from CY exhibited more types and activities than the ZY and DYC whey proteins. This study provides a theoretical basis for promoting formula milk powder production.

Invited review: Camel milk and gut health-Understanding digestibility and the effect on gut microbiota

Camel milk (CM), known for its immune-regulatory, anti-inflammatory, antiapoptotic, and antidiabetic properties, is a natural healthy food. It is easily digestible due to the high levels of β-casein and diverse secreted antibodies, exhibiting superior antibacterial and antiviral activities compared with bovine milk. β-casein is less allergic and more digestible because it is more susceptible to digestive hydrolysis in the gut; therefore, higher levels of β-casein make CM advantageous for human health. Furthermore, antibodies help the digestive system by destroying the antigens, which are then overwhelmed and digested by macrophages. The connection between the gut microbiota and human health has gained substantial research attention, as it offers potential benefits and supports disease treatment. The gut microbiota has a vital role in regulating the host's health because it helps in several biological functions, such as protection against pathogens, immune function regulation, energy harvesting from digested foods, and reinforcement of digestive tract biochemical barriers. These functions could be affected by the changes in the gut microbiota profile, and gut microbiota differences are associated with several diseases, such as inflammatory bowel disease, colon cancer, irritable bowel disorder, mental illness, allergy, and obesity. This review focuses on the digestibility of CM components, particularly protein and fat, and their influence on gut microbiota modulation. Notably, the hypoallergenic properties and small fat globules of CM contribute to its enhanced digestibility. Considering the rapid digestion of its proteins under conditions simulating infant gastrointestinal digestion, CM exhibits promise as a potential alternative for infant formula preparation due to the high β-/αs-casein ratio and protective proteins, in addition to the absence of β-lactoglobulin.

Label-free-based proteomic analysis reveals differential whey proteins of porcine milk during lactation

In this study, label-free proteomic technology was applied to analyze and compare the whey proteomes of porcine colostrum and mature milk. In total, 2993 and 2906 whey proteins were detected in porcine colostrum and mature milk, respectively. A total of 2745 common proteins were identified in the two milk samples, and 280 proteins were found to be significantly differentially expressed whey proteins in porcine milk. Gene Ontology analysis demonstrated that the differentially expressed whey proteins were primarily enriched in lipid homeostasis, oxidoreductase activity, and the collagen trimer. Kyoto Encyclopedia of Genes and Genomes analysis suggested that the phagosome and endocytosis were the crucial pathways. This study provides systematic and in-depth insight into the compositions and functional properties of whey proteins in porcine milk during different periods of lactation, which may be beneficial for the development of porcine whey proteins in the future.

Proteomic Comparisons of Caprine Milk Whole Cream Buttermilk Whey and Cheese Whey Cream Buttermilk

Buttermilk, a potential material used to produce milk fat globule membrane (MFGM), is obtained as a byproduct of butter making from milk whole cream and cheese whey cream. This study investigated the effects of rennet and acid coagulation on the protein profiles of buttermilk rennet-coagulated whey (BRW) and buttermilk acid-coagulated whey (BAW). They were compared to those of whey cream buttermilk (WCB). Rennet coagulation was more efficient in removing casein, while retaining more IgG and lactoferrin than acid coagulation. BRW had more MFGM than BAW. Butyrophilin, xanthine dehydrogenase, and mucin1 were significantly higher (P < 0.05) in BRW, while fatty acid-binding protein 3 was enriched in BAW. KEGG analysis showed that complement and coagulation cascades had the greatest differences, and the abundance of proteins involved in this signaling pathway in BRW and BAW was higher, suggesting their potential anticoagulant and anti-inflammatory activity. BAW had higher apolipoprotein A4 and transcobalamin 2, which are essential carriers for transporting long-chain fatty acids and vitamin B12 from the intestine to the blood. Therefore, BAW intake might improve lipids and vitamin B12 absorption. This study can help deepen the understanding of protein composition of MFGM-enriched whey and facilitate the production of MFGM proteins for infants and old-aged populations.

A comparison of milk fat globule membranes and whey proteomes: New insight into variation nutrient differences between Buffalo, Cow, Goat, and Yak

In this study, the whey and milk fat globule membrane (MFGM) proteomes of buffalo, cow, goat, and yak milk were analyzed using label-free proteomic technology. Totally, 1,292 MFGM proteins and 686 whey proteins were identified from these four species, and GO analysis revealed there were specific proteins with different functions in both whey (376) and MFGM (982) proteomes. The principal component analysis showed that ALB, TF, CSN1S1, and GLYCAM1 are characteristic markers of the milk for each of the four species. Furthermore, the conserved and differential in the expression of whey and MFGM proteins across the four species were identified by limma, and subsequent KEGG pathway analysis showed that immune-related proteins are both conserved and species-specific in the four species. These results provide a deepening of the understanding of the characteristics of proteins in whey and MFGMs from these four common dairy animals and new insight into developing dairy production.