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Characterization of chiral amino acids from different milk origins using ultra-performance liquid chromatography coupled to ion-mobility mass spectrometry

View Article: PubMed Central - PubMed

ABSTRACT

Milk contains free amino acids (AAs) that play essential roles in maintaining the growth and health of infants, and D-AA isomers are increasingly being recognized as important signalling molecules. However, there are no studies of the different characteristics of chiral AA (C-AA) from different milk origins. Here, UPLC coupled to ion-mobility high-resolution MS (IM-HRMS) was employed to characterize 18 pairs of C-AAs in human, cow, yak, buffalo, goat, and camel milk. The results proved that milk origins can be differentiated based on the D- to L- AA ratio-based projection scores by principal component analysis. The present study gives a deeper understanding of the D- to L- AA ratio underlying the biological functions of different animal milks, and provide a new strategy for the study of AA metabolic pathways.

No MeSH data available.


Characteristic D- to L- AA ratio (DLAArs) in milk from human, cow, yak, buffalo, goat, and camel.The DLAArs in milk origins that reached or exceeded 1.0 were asparagine in goat, glutamine in cow and camel, alanine in goat, valine in yak, and leucine in human and buffalo.
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f3: Characteristic D- to L- AA ratio (DLAArs) in milk from human, cow, yak, buffalo, goat, and camel.The DLAArs in milk origins that reached or exceeded 1.0 were asparagine in goat, glutamine in cow and camel, alanine in goat, valine in yak, and leucine in human and buffalo.

Mentions: The DLAArs were constant within individual milk origin with relative standard deviations less than 0.10 (Table 2). Most D-AA concentrations were substantially lower than L-AA concentrations. However, an interesting discovery was that the DLAArs of some AAs of certain milk origins were distinct, reaching or exceeding 1.0, including asparagine in goat, glutamine in cow and camel, alanine in goat, valine in yak, and leucine in human and buffalo (Fig. 3). Principal component analysis was conducted to study the characteristics of the DLAArs based on the milk origin, and clustering and grouping were observed in the score plots (Fig. 4). This clustering represents constant physiological intra-group states, and the grouping in the score plots indicated that the bioavailability and biological utilization of C-AAs vary widely between different milk origins. The enzymes, involved in D-AA synthesis and metabolism include D-AA oxidases, deacylases, dehydrogenases, epimerases, proteases, and racemases, the activities of which may determine the DLAArs of the different milk origins23738394041424344.


Characterization of chiral amino acids from different milk origins using ultra-performance liquid chromatography coupled to ion-mobility mass spectrometry
Characteristic D- to L- AA ratio (DLAArs) in milk from human, cow, yak, buffalo, goat, and camel.The DLAArs in milk origins that reached or exceeded 1.0 were asparagine in goat, glutamine in cow and camel, alanine in goat, valine in yak, and leucine in human and buffalo.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5385494&req=5

f3: Characteristic D- to L- AA ratio (DLAArs) in milk from human, cow, yak, buffalo, goat, and camel.The DLAArs in milk origins that reached or exceeded 1.0 were asparagine in goat, glutamine in cow and camel, alanine in goat, valine in yak, and leucine in human and buffalo.
Mentions: The DLAArs were constant within individual milk origin with relative standard deviations less than 0.10 (Table 2). Most D-AA concentrations were substantially lower than L-AA concentrations. However, an interesting discovery was that the DLAArs of some AAs of certain milk origins were distinct, reaching or exceeding 1.0, including asparagine in goat, glutamine in cow and camel, alanine in goat, valine in yak, and leucine in human and buffalo (Fig. 3). Principal component analysis was conducted to study the characteristics of the DLAArs based on the milk origin, and clustering and grouping were observed in the score plots (Fig. 4). This clustering represents constant physiological intra-group states, and the grouping in the score plots indicated that the bioavailability and biological utilization of C-AAs vary widely between different milk origins. The enzymes, involved in D-AA synthesis and metabolism include D-AA oxidases, deacylases, dehydrogenases, epimerases, proteases, and racemases, the activities of which may determine the DLAArs of the different milk origins23738394041424344.

View Article: PubMed Central - PubMed

ABSTRACT

Milk contains free amino acids (AAs) that play essential roles in maintaining the growth and health of infants, and D-AA isomers are increasingly being recognized as important signalling molecules. However, there are no studies of the different characteristics of chiral AA (C-AA) from different milk origins. Here, UPLC coupled to ion-mobility high-resolution MS (IM-HRMS) was employed to characterize 18 pairs of C-AAs in human, cow, yak, buffalo, goat, and camel milk. The results proved that milk origins can be differentiated based on the D- to L- AA ratio-based projection scores by principal component analysis. The present study gives a deeper understanding of the D- to L- AA ratio underlying the biological functions of different animal milks, and provide a new strategy for the study of AA metabolic pathways.

No MeSH data available.