• Journal of Integrative Natural Science
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• v.8 no.2
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• pp.111-116
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• 2015

Liquid chromatographic enantiomer separation of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives was performed using several chiral stationary phases (CSPs) based on polysaccharide derivatives under fluorescence detection. For enantiomer separation by normal HPLC, the non-aqueous derivatization method of ${\alpha}$-amino acid esters for NBD analytes was introduced. Among the six CSPs used in this study, the performance of Chiralpak IA was superior for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Also the convenient analytical method using polysaccharide-derived CSPs developed in this study was applied to determine the optical purity of ${\alpha}$-amino acids esters. It was investigated that the enantiomeric impurity levels of 0.02-1.73% were found after determination of enantiomeric purities of several commercially available L-amino acid methyl esters. It is expected to be quite useful for enantiomer separation of other ${\alpha}$-amino acid esters as NBD derivatives by normal HPLC.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.1
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• pp.17-26
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• 2022

Alpha-linolenic acid is an important polyunsaturated fatty acid that exhibits anticancer, anti-inflammatory, and antioxidative effects. In this study, we investigated the protective effects of alpha-linolenic acid on the cell proliferation and differentiation of C2C12 cells under essential amino acid-deficient conditions. Different concentrations of alpha-linolenic acid and essential amino acids were added to the growth and differentiation media. The concentrations of 10 µM of alpha-linolenic acid and 2% essential amino acid were chosen for subsequent experiments. Supplementation with alpha-linolenic acid and essential amino acids improved the proliferation and differentiation of C2C12 cells and significantly increased the mRNA levels of catalase, superoxide dismutase, B-cell lymphoma-2, and beclin-1 as well as the protein levels of PPARγ coactivator-1α compared to those in the controls. Moreover, supplementation with alpha-linolenic acid and essential amino acids reduced the levels of phosphorylated H2A.X variant histone, Bcl-2-associated X, p53, and light chain 3 during C2C12 cell proliferation, and increased the expression levels of myogenic factors 4 (myogenin) and 5 during C2C12 cell differentiation. Overall, we determined that alpha-linolenic acid and essential amino acids maintained the cell proliferation and differentiation of C2C12 cells via their anti-oxidative, anti-apoptotic, and anti-autophagic effects.

• KSBB Journal
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• v.27 no.3
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• pp.167-171
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• 2012

A convenient liquid chromatographic enantiomer separation of several ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives on covalently immobilized chiral stationary phases (CSPs) derived from polysaccharide derivatives was developed. The benzophenone imine derivatives of ${\alpha}$-amino acid esters were readily prepared by stirring benzophenone imine and the ${\alpha}$-amino acid ester hydrochloride salts in 2-propanol. The chromatographic conditions used on all CSPs were 0.5% or 5% 2-propanol/hexane (V/V) as the mobile phases at 1 mL/min of flow rate and UV 254 nm detection. The performance of Chiralpak IC among all CSPs was superior to that of the other CSPs for resolution of benzophenone imine derivatives of ${\alpha}$-amino acid esters. It is expected that the developed analytical method will be useful for enantiomer resolution of other ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1551-1554
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• 2010

Two diastereomeric chiral stationary phases (CSPs) were applied to the liquid chromatographic resolution of various racemic ${\alpha}$-amino methyl esters, ${\alpha}$-amino N,N-diethylamides and ${\alpha}$-amino N-propylamides. The CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (R,R)-tartaric acid unit as chiral barriers did not show any chiral recognition. In contrast, the CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (S,S)-tartaric acid unit as chiral barriers was found to show excellent chiral recognition especially for the two enantiomers of ${\alpha}$-amino N-propylamides. Some of ${\alpha}$-amino methyl esters and ${\alpha}$-amino N,N-diethylamides were also resolved on the CSP incorporating (R)-3,3'-diphenyl-1,1'-binaphtyl and (S,S)-tartaric acid unit. From these results it was concluded that the two chiral units composing the diastereomeric CSPs can show "matched" or "mismatched" effect on the chiral recognition according to their absolute stereochemistry.

• Biomolecules & Therapeutics
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• v.8 no.3
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• pp.276-280
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• 2000

In order to identify the domains of the G$_{\alpha}$16 subunit G protein that are responsible for its activation by the Interleukin-8 receptor, a serious of chimeras between G$_{\alpha}$16 and G$_{\alpha}$11 were assessed for their abilities to be activated by these receptors. Co-expression of IL-8 receptor and chimeras in which the carboxyl-terminal regions of G$_{\alpha}$11 were replaced from 30 up to 156 amino acid residues with the corresponding regions of G$_{\alpha}$16 demonstrated that C-terminal 156 amino acid residues of the G$_{\alpha}$16 were not sufficient to confer IL-8 receptor interaction specificity. Testing of a reciprocal serious of chimeras composed of G$_{\alpha}$16 sequences at the amino terminus and G$_{\alpha}$11 sequences at the carboxyl terminals revealed that sequences extending from the amino tar- minus to amino acid 209 of G$_{\alpha}$16 were sufficient to 7ndow the chimera with 75-80% of interaction specificity for 7-8-induced activation. These results suggest th,.7t combined interactions of the C-terminal 30 amino acid residues and certain domains extending from the arts.ino terminus to amino acid 209 of Gal 6 protein may be involved in its couplings to IL-8 receptor.tain domains extending from the arts.ino terminus to amino acid 209 of Gal 6 protein may be involved in its couplings to IL-8 receptor.

• KSBB Journal
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• v.28 no.6
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• pp.423-427
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• 2013

A new convenient derivatization method of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives for chiral resolution was introduced and the enantiomer separation of ${\alpha}$-amino acid esters as NBD derivatives was performed by normal HPLC using chiral columns based on polysaccharide derivatives. The NBD derivatives were readily prepared by stirring NBD-Cl and ${\alpha}$-amino acid methyl ester HCl with $NaHCO_3$ in ethanol. The performance of Chiralpak IA was superior to the other chiral stationary phases for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Owing to fluorescence detection as well as strong UV absorption, it is expected that the convenient analytical method developed in this study will be very useful for enantiomer separation of ${\alpha}$-amino acid esters as NBD derivatives on polysaccharide-derived chiral columns.

• KSBB Journal
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• v.26 no.2
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• pp.139-142
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• 2011

The chromatographic enantiomer separation of 9-anthraldimine derivatives of ${\alpha}$-amino acid methyl and ethyl esters on four polysaccharide based chiral columns was performed. The 9-anthraldehyde Schiff base derivatives of ${\alpha}$- amino acid esters were readily synthesized by stirring the ${\alpha}$- amino acid ester hydrochloride salts with 9-anthraldehyde in the presence of 1,8-diazabicyclo [5.4.0]undec-7-ene as a base and anhydrous $MgSO_4$. Chiralcel OD or Chiralcel OD-H showed the greatest enantiomer resolution of 9-anthraldimine derivatives of ${\alpha}$-amino acid methyl and ethyl esters. The L-enantiomers of all the analytes were preferentially retained on Chiralcel OD or Chiralcel OD-H. This analytical method was applied in the determination of optical purities of several commercially available D- or L-${\alpha}$-amino acid methyl esters.

• KSBB Journal
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• v.30 no.4
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• pp.197-201
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• 2015

Liquid chromatographic enantiomer separation of ${\alpha}$-amino acids and their methyl and ethyl esters as fluorenylmethoxycarbonyl (FMOC) derivatives was performed using a recently developed chiral column (Chiralpak IE) based on polysaccharide derivative under simultaneous UV detection and fluorescence detection. The degree of enantiomer separation of ${\alpha}$-amino acid esters as FMOC derivatives is generally higher than that of the corresponding ${\alpha}$-amino acids. Especially, ${\alpha}$-amino acid methyl esters showed the greatest enantioseparation. As this method developed in this study can be applied to determine the chemical and optical purity of ${\alpha}$-amino acids and esters, it is expected to be quite useful for their chiral separation using Chiralpak IE.

• Journal of Nutrition and Health
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• v.12 no.1
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• pp.31-41
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• 1979

Free amino acid in ethanol extracts and total amino acids in hydrolysates of eleven species of edible mushrooms were analyzed and determinated the contents five kind of new amino acid by means of amino acid autoanalyzer and gas liquid chromatography. The result obtained from this study are as follows. 1) Five kind of new amino acid turned out to be ${\alpha}$-aminobutyric acid, allo-isoleucine, ethanolamine, $\gamma$-aminobutyric acid and ornithine. 2) By means of amino acid autoanalyzer, the monoethanolamine was identified on the chromatogram ahead of alanine, ${\alpha}$-aminobutyric acid between peak of threonine and glycine, allo-isoeleucine between peak of valine and leucine, isoleucine, ${\gamma}$-aminobutyric acid followed by proline between peak of leucine, isoleucine and methionine and ornithine between peak of phenylalanine and tyrosine 3) By means of Gas liquid chromatography, the ${\alpha}$-aminobutyric acid was identified on the chromatogram between peaks of alanine and valine, allo-isoleucine between peaks of methionine and isoleucine, monoethanolamine followed by ${\gamma}$-aminobutyric acid between peaks of phenylalanine and ammonia, ornithine between the peaks of ammonia and lysine. 4) Of five amino acids which were identified, ornithine was the highest of its content in the mushroom extracts, and allo-isoleucine, ethanolamine, and ${\gamma}$-aminobutyric acid came next in decreasing order. 5) Also which were identified, ornithine was the highest of its content in the hydrolysates, and ${\alpha}$-aminobutyric acid, ${\gamma}$-aminobutyric acid, allo-isoleucine came next in decreasing order, ethanol extracts and hydrolysates of Auriculariaauricula-Judae(Fr.) $Qu\acute{e}l$ species didn't contain any of five kind of new amino acid. Ornithine also was the highest in the hydrolysates of ll mushrooms.

• Preventive Nutrition and Food Science
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• v.3 no.4
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• pp.368-373
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• 1998

Plasma amino acid concentration and Urinary exretion of free amino acids were measured in health female vegetarians(n=20, 19.9 $\pm$0.43 years old ) and age-mateched imnivores(n=20, 21.9$\pm$0.38years old) in Korean. differences infasting plasma amino acid concentrations and plasma aminogram pattern were not spectacular between the vegetarian and omnivore controls. Compared to the omnivores, vegetarians showed significantly lower plasma levels of methionine , phenylalanine, $\alpha$-aminobutyrate, citrulline, phosposerine and tarurine, and significantly higher plasma concentrations of arginine, $\alpha$-aminobutyrate, cirtrulline, phosphosierine and taurine, and significantly higher plasma concentrations of arginine, $\alpha$-aminoadipate, asparagine, aspartate, glutamate and ornithine. Although these differences were statistically significant, they were all within the normal range (21~70% differences )for human adults. Most of the urinary amino acids (nmol/mg creatinine or $\mu$mol/24 hr urine) were excreted to significantly lesser degree in vegetarians than was the case in omnivore controls. For almost every individual free amino acid, plasma concentration did not significantly correlate with urinary excretion level. These results indicate that vegetarians excreted less amino acids in their urine than did dominivores, most probably in an effort to maintain amino acid homeostasis to an altered dietary protein intake level and/or amino acid composition of their diets.