Journal article

Publication year: 2014

Pages: 2241-2257

Journal: Amino Acids

Volume number: 46

Issue number: 9

ISSN: 0939-4451

eISSN: 1438-2199

DOI Link: https://doi.org/10.1007/s00726-014-1770-7

Publisher: Springer

Abstract: 
Whereas an abundance of literature is available on the occurrence of common proteinogenic amino acids (AAs) in edible fruits of the date palm (Phoenix dactylifera L.), recent reports on non-proteinogenic (non-coded) AAs and amino components are scarce. With emphasis on these components we have analyzed total hydrolysates of twelve cultivars of date fruits using automated ion-exchange chromatography, HPLC employing a fluorescent aminoquinolyl label, and GC-MS of total hydrolysates using the chiral stationary phases Chirasil(A (R))-L-Val and Lipodex(A (R)) E. Besides common proteinogenic AAs, relatively large amounts of the following non-proteinogenic amino acids were detected: (2S,5R)-5-hydroxypipecolic acid (1.4-4.0 g/kg dry matter, DM), 1-aminocyclopropane-1-carboxylic acid (1.3-2.6 g/kg DM), gamma-amino-n-butyric acid (0.5-1.2 g/kg DM), (2S,4R)-4-hydroxyproline (130-230 mg/kg DM), l-pipecolic acid (40-140 mg/kg DM), and 2-aminoethanol (40-160 mg/kg DM) as well as low or trace amounts (< 70 mg/kg DM) of l-ornithine, 5-hydroxylysine, beta-alanine, and in some samples (< 20 mg/kg DM) of (S)-beta-aminoisobutyric acid and (< 10 mg/kg DM) l-allo-isoleucine. In one date fruit, traces of alpha-aminoadipic acid could be determined. Enantiomeric analysis of 6 M DCl/D2O hydrolysates of AAs using chiral capillary gas chromatography-mass spectrometry revealed the presence of very low amounts of d-Ala, d-Asp, d-Glu, d-Ser and d-Phe (1.2-0.4 %, relative to the corresponding l-enantiomers), besides traces (0.2-1 %) of other d-AAs. The possible relevance of non-proteinogenic amino acids in date fruits is briefly addressed.

Harvard Citation style: Ali, H., Alhaj, O., Al-Khalifa, A. and Brueckner, H. (2014) Determination and stereochemistry of proteinogenic and non-proteinogenic amino acids in Saudi Arabian date fruits, Amino Acids, 46(9), pp. 2241-2257. https://doi.org/10.1007/s00726-014-1770-7

APA Citation style: Ali, H., Alhaj, O., Al-Khalifa, A., & Brueckner, H. (2014). Determination and stereochemistry of proteinogenic and non-proteinogenic amino acids in Saudi Arabian date fruits. Amino Acids. 46(9), 2241-2257. https://doi.org/10.1007/s00726-014-1770-7