• Applied Biological Chemistry
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• v.38 no.1
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• pp.13-19
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• 1995

In order to produce phenylalanine without tyrosine co-production, we constructed various temperature-controllable expression vectors by insertion of lower expression of the tyrA gene into the plasmid pSY130-14. And tyrosine revertant to cultivate without addition of tyrosine, was selected from Escherichia coli strain AT2471[tyrA , thi ] by spontaneous mutation. The strain AT2471 harbouring plasmid pSY146A and the tyrosine revertant 5 harbouring plasmid pSY111-14 produced 12 g/l and 15 g/l of phenylalanine respectively in a 2.5 l jar fermenter at a constant temperature of $39^{\circ}C$ after 55 hours cultivation.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.2
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• pp.86-92
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• 2016

Purpose: The $BH_4$ loading test is an important test that distinguishes PKU from $BH_4$ deficiency and identifies the $BH_4$ reactivity of PKU patients. Phenylalanine and $BH_4$ loading tests are useful methods that can shorten the length of hospital stay while improving patients' convenience. However, sufficient research on the dose of phenylalanine loading and $BH_4$ administration time after the loading has not been carried out. The present study investigates the effectiveness of the existing phenylalanine loading method by analyzing the medical records of six patients who underwent the $BH_4$ loading test after taking 100 mg/kg of phenylalanine patients. Methods: The medical records of six patients who underwent the $BH_4$ load test after taking 100 mg/kg of phenylalanine were examined out of 207 patients who were followed up in the Genetic Metabolic Clinic in Soonchunhyang University Hospital. All of the six patients had a low phenylalanine diet. First, they were taking 100 mg/kg of phenylalanine. 3 hours later, 20 mg/kg of $BH_4$ were loaded. The phenylalanine levels in the blood were continuously measured at 1, 2, 4, 6, 8, 12, and 24 hours by setting the time the $BH_4$ was loaded as the basal. Results: The average of the highest phenylalanine concentrations of six patients was $20.0{\pm}11.70mg/dL$. One reached the highest concentration seven hours after taking phenylalanine; another reached it five hours after that, and the remaining three reached it four hours after that. Only one patient reached the highest concentration within three hours. The phenylalanine levels of four out of six patients (66%) rose above $400{\mu}mol/L$ after being loaded with phenylalanine. The phenylalanine levels of the remaining two were 6.1 mg/dL ($366{\mu}mol/L$) and 5 mg/dL ($300{\mu}mol/L$), respectively. Conclusion: One of six patients (16%) reached the highest concentration three hours after taking 100 mg/kg of phenylalanine and four patients (66%) reached $400{\mu}mol/L$ or higher phenylalanine levels. There were patients whose phenylalanine levels did not rise above $400{\mu}mol/L$ using a commonly known test method; moreover, this method had the disadvantage of reaching the highest concentration after more than three hours. Therefore, it is considered that taking 200 mg/kg or more of phenylalanine and performing $BH_4$ loading four to six hours after taking phenylalanine are helpful in proper diagnosis.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.604-607
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• 2000

Preparation for the D-phenylalanine using chemo-enzymatic reaction was investigated. D,L-5-benzylhydantoin was synthesized chemically from L-phenylalanine and converted to N-carbamoyl-D-phenylalanine by the immobilized hydantoinase. The pH and temperature affected the solubility and racemization rate of benzylhydantoin. The optimal temperature and pH of the process were $50^{\circ}C$, 8.5, respectively and the conversion yield hadn't much difference with the hydantoinase content in 10hrs. This produced N-carbamoyl-D-phenylalanine was transformed chemically into D-phenylalanine.

• Bulletin of the Korean Chemical Society
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• v.15 no.5
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• pp.387-390
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• 1994

The conversion of trans-cinnamic acid to phenylalanine using phenylalanine ammonia lyase (PAL) was examined. The optimum concentration of trans-cinnamic acid for the reaction was observed at 100 mM in cells and at 20 mM in cell free extracts, respectively. The production of L-phenylalanine was increased in both experiments as the concentration of ammonia was increased up to 10 M. The optimal pHs for the maximal conversion of trans-cinnamic acid to L-phenylalanine were 9.5 and 9.0 in experiments carried out with cells and with cell free extracts, respectively.

• Korean Journal of Microbiology
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• v.28 no.2
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• pp.169-173
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• 1990

For the overproduction of L-phenylalanine using Escherichia coli, the authors constructed various recombinant plasmids including pMW 10, pMW 11 and pMW 12. The $aroF{FR}$ and $pheA^{FR}$ genes for the production of L-phenylalanine were isolated from Escherichia coli MWEC 101-5 strains. The productivity and atability of Escherichia coli regulatory mutants containing recombinant plasmids were investigated to evaluate the efficiency of the $aroF^{FR}$ and $pheA^{FR}$ genes. The MWEC 101-5/pMW 11 strain produced 24.3g/l of L-phenylalanine while its stability was 73.8 percent. The specific activity of prephenate dehydratase in the MWEC 101-5/pMW 11 strain increased by 26-fold compared with that of Escherichia coli K-12.

• Applied Biological Chemistry
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• v.31 no.4
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• pp.376-381
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• 1988

The optimal reaction conditions were investigated to produce L-phenylalanine from transcinnamic acid and ammonia by Rhodotorula glutinis IFO 0559. The highest amount of L-phenylalanine was produced when the reaction mixture containing 200mM of traps-cinnamic acid, 4M of $NH_4OH$, 250mM of $(NH_4)_2SO_4$, 0.005% of cetylpyridinium chloride (pH 10.5) and 50mg/ml of dry cell was used. Among the nonaqueous organic solvents, petroleum ether was the most effective on the production of L-phenylalanine. The optimal concentration of petroleum ether in the reaction mixture was 50%. Under the optimal conditions, 21.1g/l of L-phenylalanine was produced in 12hr, and the yield was 63.9% based on transcinnamic acid.

• Korean Journal of Pharmacognosy
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• v.27 no.4
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• pp.359-365
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• 1996

In order to product the saikosaponin which is one of the secondary product from Bupleurum falcatum efficiently through the tissue culture, several levels of agar and gellan gum as the gelling agent, 2,4-D as the growth regulator, and L-phenylalanine as the precursor were used with single or combination treatment on MS basal medium. Gellan gum was more effective than agar as the gelling agent in fresh and dry weight increase of callus induced from Bupleurum falcatum leaf segment. Gellan gum medium supplemented with L-phenylalanine produced 1.6 times of fresh weight more than that of agar. The fresh weight was remarkably high in gellan gum when the calli was treated with the combination of 2,4-D and L-phenylalanine similar to the single treatment of 2,4-D or L-phenylalanine. However, the saikosaponin content in callus was high in gellan gum with the single treatment of L-phenylalanine. Especially, the saikosaponin content in gellan gum supplemented with 1.0mg/L L-phenylalanine was 2 times(2.4 mg/g) higher than that in agar medium supplemented with 0.1 mg/L 2,4-D(0.9 mg/g).

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.8
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• pp.1138-1144
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• 2012

This study was conducted to evaluate the efficacy of the dipeptide form of phenylalanine as a new source of amino acid in terms of growth performance and whole-body amino acid composition in comparison to the free form for red seabream (Pagrus major). Fish ($1.46{\pm}0.001g$) were fed four isonitrogenous and isocaloric experimental diets containing 0.7 or 1.4% phenylalanine either in free or dipeptide form. A feeding trial was carried out in three replicates and the fish were fed to apparent satiation for six weeks. At the end of the feeding trial, feed intake of fish was influenced by both phenylalanine form and level and significantly higher values were obtained at an inclusion level of 0.7% and by the use of dipeptide form. However, the other growth parameters did not significantly differ among treatments. Whole-body amino acid compositions revealed no significant changes in concentrations of both essential and non-essential amino acids regardless of the increase in phenylalanine levels or the use of its different forms. The finding in this study indicates that juvenile red seabream can utilize dipeptide phenylalanine as efficiently as free form without any undesirable effects on growth performance or whole-body amino acid composition.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.78-78
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• 2010

The Adsorption structures of phenylalanine on Ge(100) surface have been investigated as a function of coverage using high-resolution photoemission spectroscopy (HRPES) and density functional (DFT) calculation. To converge these experimental and theoretical conclusion, we systematically performed HRCLPES measurements and DFT calculation for various coverage in the adsorption structures of phenylalanine molecules on the Ge(100) surface. In this study, we found two different adsorption structure as a function of coverage in phenylalanine on Ge(100), monitoring three core level spectra (Ge 3d, C 1s, N 1s, and O 1s) using HRPES Through analysis of the binding energies, we confirmed that O-H dissociated and N dative-bonded structure emerges at low coverage (0.10 ML), which is the same to the result of glycine and alanine on Ge(100) system, whereas O-H dissociation structure also appears at higher coverage. Moreover, we observed the shape of phenyl group being included in phenylalanine is changed from flat to tilting structure at final state using DFT calculation. Through the spectral analysis for phenylalanine, we will demonstrate variation of coverage dependent structural change for phenylalanine on Ge(100) surface using experimental (HRPES) and theoretical studies (DFT calculation).

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.205-205
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• 2011

The self-assembly of ${\gamma}$-phenylalanine on Au(111) at 150 K was investigated using scanning tunneling microscopy (STM). Phenylalanine can potentially form two-dimensional (2D) molecular networks through hydrogen bonding (through the carboxyl and amino groups) and ${\pi}-{\pi}$ stacking interactions (via aromatic rings). We found that ${\gamma}$-phenylalanine molecules self-assembled on Au(111) surfaces into well-ordered structures such as ring-shaped clusters (at low and intermediate coverages) and 2D molecular domains (intermediate and monolayer coverages), whereas ${\alpha}$-phenylalanine molecules formed less-ordered structure on Au(111). The self-assembly of ${\gamma}$- but not ${\alpha}$-phenylalanine may be related to the flexibility of the carboxyl and amino groups in the molecule. Moreover, as expected, the 2D molecular network of ${\gamma}$-phenylalanine on Au(111) was mediated by a combination of hydrogen bonding and ${\pi}-{\pi}$ stacking interactions.