• Journal of Nutrition and Health
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• v.19 no.4
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• pp.246-254
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• 1986

Weanling female Sprague Dawley rats were fed d diets containing 22mg pyridoxine. BCI/kg diet (control diet) and l.2mg pyridoxine. BCI/kg diet (deficient diet). One control group and one defi­c dent group were fed their diet throughout growth, g gestation and lactation. After the pups were born and weaned, the deficient group was divided into two groups. One switched to control diet(supple­I mented group) and the other continued the same d deficient diet( deficient group) until 10 week -old. The liver mitochondrial and cytosolic asparate a aminotransferase activity and pyridoxal phosphate content were determined in offspring rats. The aspartate aminotransferase activities in both liver mito$\phi$ondrial and cytosolic fractions of den­d cient group were significantly lower than those of controls, but there were no significant differences between two groups after addition of 1O^{-4}M pyri­d do뼈I phosphate to the medium. By pyridoxine s supplementation after weaning, the reduced aspar­a tate aminotnmsferase activities were only partialy I restored to control levels. The pyridoxal phospha­t te content of deficient group in Iiver mitochondr­ial and cytosoIic fractions were alo significantly different from those of controls, but readily restored by dietary supplementation. These results suggest that there is a quantitative and a qualitative changes of aspartate amino trans­f ferase and pyridoxal phosphate in liver mitochon­d drial and cytosolic fraction by long-term pyrido­x xine deficiency and these reductions can partially recovered by dietary pyridoxine supplementation after weaning.

• The Plant Pathology Journal
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• v.37 no.6
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• pp.673-680
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• 2021

Acidovorax citrulli (Ac) is the causative agent of bacterial fruit blotch disease in watermelon. Since resistant cultivars have not yet been developed, the virulence factors/mechanisms of Ac need to be characterized. This study reports the functions of a putative pyridoxal phosphate-dependent aminotransferase (PpdaAc) that transfers amino groups to its substrates and uses pyridoxal phosphate as a coenzyme. It was observed that a ppdaAc knockout mutant had a significantly reduced virulence in watermelon when introduced via germinated-seed inoculation as well as leaf infiltration. Comparative proteomic analysis predicted the cellular mechanisms related to PpdaAc. Apart from causing virulence, the PpdaAc may have significant roles in energy production, cell membrane, motility, chemotaxis, post-translational modifications, and iron-related mechanisms. Therefore, it is postulated that PpdaAc may possess pleiotropic effects. These results provide new insights into the functions of a previously unidentified PpdaAc in Ac.

• BMB Reports
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• v.41 no.5
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• pp.408-413
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• 2008

Pyridoxal-5'-phosphate phosphatase (PLPP) catalyzes the dephosphorylation of pyridoxal-5'-phosphate (PLP). A human brain PLPP gene was fused with a PEP-1 peptide and produced a genetic in-frame PEP-1-PLPP fusion protein. The purified PEP-1-PLPP fusion protein was efficiently transduced into PC12 cells in a time- and dose-dependent manner when added exogenously to culture media. Once inside the cells, the transduced PEP-1-PLPP fusion protein was stable for 36 h. The concentration of PLP was markedly decreased by the addition of exogenous PEP-1-PLPP to media pretreated with the vitamin $B_6$ precursors; pyridoxine, pyridoxal kinase and pyridoxine-5'-phosphate oxidase into cells. The results suggest that the transduction of the PEP-1-PLPP fusion protein can be one mode of PLP level regulation, and to replenish this enzyme in the various neurological disorders related to vitamin $B_6$.

• Korean Journal of Food Science and Technology
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• v.9 no.3
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• pp.183-189
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• 1977

Studies were made of the continuous production of Pyridoxal 5'-phosphate (pyridoxal-p) on simultaneously immobilized cell column. Whole-cell of Pseudomonas polycolor having high activity of pyridoxine 5'-phosphate (pyridoxine-p) oxidase and Kloeckera sp. No. 2201 having high activity of catalase were used as the enzyme materials. The enzyme sources were entrapped in a polyacrylamide gel. Enzymatic properties of the simultaneously immobilized cells were investigated, comparing with those of the mixed whole-cells of the microorganisms. The simultaneously immobilized cells had higher enzyme activity than singly immobilized cells of Pseudomonas polycolor. From this result, the simultaneously immobilized pyridoxine-p oxidase-catalase system could be available to exert a protective effect upon the pyridoxine-p oxidase by destroying $H_2O_2$ which is a by-product of pyridoxine-p oxidation. The optimum pH was 9.0 for the immobilized cells and the whole-cells. The optimum temperature was $45^{\circ}C$ for the immobilized cells and $40^{\circ}C$ for the whole-cells. The pyridoxine-p oxidase of the immobilized cells were activated by $Hg^{++}$ and some SH-compounds.

• BMB Reports
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• v.29 no.4
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• pp.335-342
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• 1996

Porcine liver cysteinesulfinic acid decarboxylase was purified approximately 460-fold by means of ammonium sulfate fractionation and sequential column chromatographic separation with Sephadex G-100, DEAE-cellulose and hydroxylapatite. The enzyme has a flat pH profile with maximum activity occurring between pH 6.0 and 7.6. Pyridoxal 5'-phosphate must be present in all buffers used for purification procedures in order to stabilize the enzyme. Addition of sulfhydryl reagents such as 2-mercaptoethanol are also necessary to maintain maximum enzyme activity throughout purification. The absorption spectrum shows that cysteinesulfinic acid decarboxylase is a pyridoxal 5' -phosphate-containing protein. The major absorption is at 280 nm with two smaller absorption regions, one at 425 nm which is ascribed to a Schiffs base between pyridoxal phosphate and protein, and another at 325 nm which is thought to be due to the interaction of 2-mercaptoethanol with the Schiffs base. A number of divalent cations tested did not affect enzyme activity with the exception of mercury, copper, and zinc which are inhibitory. The partially purified enzyme has an apparent $K_m$ of 0.94 mM for cysteinesulfinate. Cysteic acid is a competitive inhibitor of the enzyme with a $K_i$ of 1.32 mM. The molecular weight of the enzyme was estimated to be about 79,600 by using Sephadex G-200 column chromatography.

• The Plant Pathology Journal
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• v.39 no.3
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• pp.235-244
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• 2023

Acidovorax citrulli (Ac) is a phytopathogenic bacterium that causes bacterial fruit blotch (BFB) in cucurbit crops, including watermelon. However, there are no effective methods to control this disease. YggS family pyridoxal phosphate-dependent enzyme acts as a coenzyme in all transamination reactions, but its function in Ac is poorly understood. Therefore, this study uses proteomic and phenotypic analyses to characterize the functions. The Ac strain lacking the YggS family pyridoxal phosphate-dependent enzyme, AcΔyppAc(EV), virulence was wholly eradicated in geminated seed inoculation and leaf infiltration. AcΔyppAc(EV) propagation was inhibited when exposed to L-homoserine but not pyridoxine. Wild-type and mutant growth were comparable in the liquid media but not in the solid media in the minimal condition. The comparative proteomic analysis revealed that YppAc is primarily involved in cell motility and wall/membrane/envelop biogenesis. In addition, AcΔyppAc(EV) reduced biofilm formation and twitching halo production, indicating that YppAc is involved in various cellular mechanisms and possesses pleiotropic effects. Therefore, this identified protein is a potential target for developing an efficient anti-virulence reagent to control BFB.

• Journal of Nutrition and Health
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• v.28 no.4
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• pp.321-330
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• 1995

Concentrations of total vitamin B-6 in human milk as well as individual, B-6 vitamers have important implications for the nutritional management of breast-fed(BF) infants. Vitamin B-6 status was assessed in 3 groups of infants : two groups preterm (PT) BF infants whose mothers were supplemented with 2 or 27mg pyridoxine(PN)-HCI ; a sub group of formula-fed (FF) PT infants. Mothers and infants were assessed weekly during the 28-day post feeding. Throughout the neonatal period, levels of total vitamin B-6 and percentages of pyridoxal(PL) in breast milk were lower in PT than T mothers, even in mothers supplemented with 27mg PN-HCI. Total vitamin B-6 levels in PT milk paralleled maternal supplementation but percentage distributions of B-6 vitamers did not change. Vitamin B-6 intakes of BF preterm infants paralleled their mothers' level of infants in the 2mg group was suggested by vitamin status parameters. Vitamin B-6 inadequacy of infants correlated with their plasma pyridoxal-5-phosphate(PLP) levels and erythrocyte alanine aminotransferase(E-ALAT) activity; all parameters such as plasma PLP, PL/PLP ratio and stimulation % of E-ALAT were highest for FF PT infants. The positive correlation of vitamin B-6 levels in breast milk gestational age may contraindicate its adequacy for some PT infants.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.74-74
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• 1995

GABA transaminase is inactivated by preincubation with p$^1$, p$^2$-bis(5'-pyridoxal) diphosphate at pH 7.0. The inactivation under pseudo-first order conditions proceeds at a slow rate (K$\_$obs/=0.035 min$\^$-1/). The degree of labeling of the enzyme by p$^1$, p$^2$-bis(5'-pyridoxal) diphosphate was determined by absorption spectroscopy, The blocking of 2 lysyl residues/dimer is needed for inactivation of the transaminase. The time course of the reaction is significantly affected by the substrate ${\alpha}$-ketoglutarate, which afforded complete protection against the loss of the catalytic activity. Whereas cofator pyridoxal phosphate failed to prevent the inactivation of the enzyme. Therefore, it is postulated that binding of ${\alpha}$-ketoglutarate tn lysyl residues is the major factor contributing to stabilization of the catalytic site and bifuctional reagent p$^1$, p$^2$bis(5'-pyridoxal) diphosphate blocks lysyl residues other than those involved in the binding of the cofactor.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.736-738
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• 2003

Ornithine decarboxylase (ODC) is the key enzyme in the synthetic pathway of polyamines. This enzyme is a homodimeric and a pyridoxal 5-phosphate (PLP) dependent enzyme. We have isolated, a cDNA clone encoding ODC from brain cDNA library constructed from flounder (Paralichthys olivaceus). The ODC cDNA contained a complete ORF consisting of 460 amino acids and one stop codon with comparison to nucleotide sequences of the flounder, zebrafish and rat ODC genes, the ODC genes were highly conserved. The transcription of ODC was analyzed with reverse transcription-polymerase chain reaction (RT-PCR) species in brain, kidney, liver, and embryo.

• BMB Reports
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• v.55 no.9
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• pp.439-446
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• 2022

Pyridoxal 5'-phosphate (PLP)-dependent enzymes are ubiquitous, catalyzing various biochemical reactions of approximately 4% of all classified enzymatic activities. They transform amines and amino acids into important metabolites or signaling molecules and are important drug targets in many diseases. In the crystal structures of PLP-dependent enzymes, organic cofactor PLP showed diverse conformations depending on the catalytic step. The conformational change of PLP is essential in the catalytic mechanism. In the study, we review the sophisticated catalytic mechanism of PLP, especially in transaldimination reactions. Most drugs targeting PLP-dependent enzymes make a covalent bond to PLP with the transaldimination reaction. A detailed understanding of organic cofactor PLP will help develop a new drug against PLP-dependent enzymes.