• Microbiology and Biotechnology Letters
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• v.15 no.2
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• pp.80-83
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• 1987

During the enzymatic production of L-phenylalanine exploiting L-phenylalanine ammonia lyase(E.C 4.3.1.5) and trans-cinnamic acid, the conversion yield of L-phenylalanine and the stability of L-phenylalanine ammonia-lyase per so or induced Rhodotorula glutinis IFO 0559 were investigated. And the glycerol added to the conversion reaction as stabilizer had effect only on L-phenylalanine and made it possible to obtain the 80％ conversion yield from trans-cinnamic acid. In addition, the more rapid and reliable method than the thin layer chromatography for determining the conversion yield will be disscused.

• Microbiology and Biotechnology Letters
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• v.16 no.3
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• pp.238-245
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• 1988

Studies were made on the regulation of chorismate mutase and prephenate dehydratase of a species of Intrasporangium, a phenylalanine producing Actinomycete isolated from soil. Two distinctly regulated species of chorismate mutase, designated CM I and CM IIwere resolved by DEAE Cellulose and DEAE Sephadex A 50 chromatography. The activity of CM II was inhibited by L-tyrosine, whereas that of CM I appeared to be unregulated. Single species of prephenate dehydyatase was also separated in the same purification steps. The activity of the enzyme was strongly feedback inhibited by L-phenylalanine, but by L-tyrosine or L-methionine it was rather slightly stimulated. Synthesis of chorismate mutase was not influenced by the presence of phenylalanine, tyrosine or tryptophan, whereas prephenate dehydratase was found to be subject to strong feedback repression by L-phenylalanine. The rate of repression was 94% at the concentration of 1mM L-phenylalanine but the repression was completely offset by the presence of 5mM tyrosine. The critical regulatory site of the phenylalanine terminal biopathway was, therefore, proved to be the second reaction which was catalyzed by the L-phenylalanine inhibitable and repressible prephenate dehydratase.

• Korean Journal of Pharmacognosy
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• v.27 no.4
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• pp.354-358
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• 1996

This experiment was conducted to find out the effects of L-phenylalanine on the saikosaponin content of callus induced from Bupleurum falcatum leaf segments. In the fresh and dry weight of callus, the addition of 2,4-D than L-phenylalanine was significantly effective. However, the L-phenylalanine treatment rather than 2,4-D was effective for high saikosaponin accumulation in the callus of Bupleurum falcatum.

• Korean Journal of Microbiology
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• v.28 no.2
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• pp.174-179
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• 1990

In order to overproduce L-phenylalanine, various kind of regulatory mutants were isolated from parental Escherichia coli K-12. MWEC 83 Producing 7.4g/l of L-phenylalanine has been derived as a tyrosine and tryptophan double auxotrophic mutant. To produce L-phenylalanine without adding L-tyrosine and L-tryptophan, revertant strain MWEC 101 was isolated from MWEC 83. Further various analogues and valine resistant mutants were isolated from MWEC 101. MWEC 101-5 was the most excellent strain that produced 17.9g/l of L-phenylalanine after having been cultivated for 54 hours in 15% glucose medium. It was disclosed that activities of rate-limiting enzymes including chorismate mutase and prephenate dehydratase in MWEC 101-5 were desensitized to 2mM L-phenylalanine in the enzyme reaction mixture and that activities level of 3-deoxy-D-arabino-heptulosonic acid-7-phosphate synthase and prephenate dehydratase were increased more than 20 times over those of the parental strain.

• KSBB Journal
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• v.6 no.3
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• pp.321-325
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• 1991

In thisstudy, effects of medium components on microbial production of L-phenylalanine by Corynebacterium glutamicum were investigated. The effect of carbon source on the production of L-phenylalanine was significant. Molasses enhanced the production of L-phenylalanine compared to sucrose, glucose, fructose, or their mixture. It was noticed that trace salts were required for the cell growth and product formation in the minimal medium, but excess amounts of trace salts had no effect on the production of L-phenylalanine. It was also found that optimum amounts of biotin and thiamine were required for the cell growth and the production of L -phenylalanine.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.270-277
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• 1988

Microorganisms isolated from soil (150 strains), fungi (39 strains), yeasts (9 strains) and Streptomyces species (39 strains) were assayed for L-phenylalanine ammonia-lyase(PAL) activity. 17 strains of fungi and 46 strains of soil isolates were proved to produce PAL, Aspergillus panamensis, Penicillium varioti and 11 soil isolates showed comparatively large PAL activity. When PAL activity was assayed with cell-free extracts of these 13 strains and 7 strains of Rhodotorula and Rhodosporidium geni, Rhodosporidium toruloides (IFO 0559) showed the highest PAL activity with 0.333 units per g of the wet cell weight.

• 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).

• 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.

• 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.