• Journal of Nutrition and Health
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• v.32 no.4
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• pp.369-375
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• 1999

Hyperthroidism in known to alter the activity of a number of enzymes involved in the catabolism of histidine to CO2. 10-Formyltetrahydrofolate dehydrogenase(EC 1.5, 1.6, 10-formyl-THE dehydrogenase) catalyzes the NADP-dependent conversion of 10-formyltetrahydrofolate to tetrahydrofolate and CO2. In previous studies, 10-formyl-THF dehydrogenase purified from rat and pig liver was coidentified with the cytosolic folate-binding protein. In this study, we investigated the effects of feeding thyroid powder (TP) and thiouracil(TU) on the folate-binding properties of 10-formyl-THE dehydrogenase, the uptake of an injected dose of [3H] folate, and the metabolism of labeled folate to pteroylopoly-${\gamma}$-glutamate in rat liver. The initial hepatic uptake(24hr) of the labeled folate dose was higher in TU-rats and slightly higher in TP-rats in controls. With longer time periods, decreased hepatic uptake of labeled folate was observed in TP-animals compared to euthroid animals, and high levels of hepatic uptake of labeled folate were maintained in TU-animals. This data shows that high levels of thyroid hormone decreased the retention of folate in rat liver. Folate polygutamate chain length was shorter in TU-rats than controls, which suggests that thyroid states do not affect the ability to synthesize pteroylpolyglutamates and that folate polyglutamate might be modulated by altered folate pool size. The ability of 10-formyl-THE dehydrogenase to bind folate in rat liver was similar in both TP-and TU-rats although dehydrogenase activity was changed by thyroid sates.

• Macromolecular Research
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• v.10 no.1
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• pp.49-52
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• 2002

Rod-coil amphiphilic block copolymers, PALG-PEOs, poly(alkyl $\alpha$, L-glutamate-co-ethylene oxide)s, were successfully synthesized in three steps: 1) esterification of L-glutamic acid, 2) synthesis of ${\gamma}$-alkyl L-gultamate N-carboxyanhydride, and 3) polymerization of NCA monomers. These molecules form polymeric micelles with the hydrophobic core and hydrophilic corona in aqueous solution, which were characterized by light scattering and static fluorescence measurement.

• Journal of Nutrition and Health
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• v.10 no.4
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• pp.84-91
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• 1977

엽산의 결핍은 대혈구성 빈혈(macrocytic and/or megaloblastic anemia)을 일으킨다. 체내에서 엽산은 합성될 수 없는 것으로 알려져, 식품을 통하여 섭취하여야 한다. 이에, 한국인 식생활의 기본을 이루고 있는 쌀, 콩 및 채소류의 식품에 포함된 엽산치를 미생물학적인 측정방법에 따라 분석하였다. Streptococcus faecalis보다 Lactobacillus casei미생물을 사용하여 측정한 방법이, 인간에게 이용될 수 있는 보다 정확한 엽산치로 밝혀졌다. 산화되기 쉬운 형태로 된 labile folate를 보호하기 위한 ascorbic acid의 첨가는, 각 식품에 포함된 엽산치를 증가 시켰다. 결합형으로 존재하는 polyglutamates를 유리형으로 하기 위하여 conjugase enzyme을 사용하였으며, 식품에 따른 화학적 조성은 주로 polyglutamyl form이나 각 식품에 따라 큰 차이가 있는 것으로 나타났다. Lactobacillus casei을 사용하여 측정된 각 식품의 엽산치는, 배추 34.5, 당근17.8, 오이 25.3, 가지 24.7, 쑥갓 76.5, 마늘 3.1, 파 40.2, 완두콩 68.7, 풋고추 27.1, 강남콩 66.9, 부추 64.1, 상치 39.3, 양파 4.3, 시금치 150.7, 호박 26.1, 무우 40.3, 백미 29.9 ug으로 각기 식품 100g 중에 함유됨을 보였다.

• Food Science of Animal Resources
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• v.22 no.1
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• pp.55-58
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• 2002

The economical producing method of casein phosphopeptide (CPP) and the physicochemical properties related to the solubilization of calcium were studied. Firstly, The compositions of the purified CPP-III were 13.1% of nitrogen, 2.3∼2.4% of phosphate and the ratio of N/P was 5.4∼5.6. In consideration of economic aspects, the preparation method of the CPP- I and II which were lower purity than the CPP-III was established. The physico-chemical property of the CPP was compared with the enzymically dephosphorylated CPP. CPP and polyglutamate effectively inhibited the formation of insoluble calcium phosphates at physiological pH.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.109-117
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• 2020

Cre recombinase is widely used to manipulate DNA sequences for both in vitro and in vivo research. Attachment of a trans-activator of transcription (TAT) sequence to Cre allows TAT-Cre to penetrate the cell membrane, and the addition of a nuclear localization signal (NLS) helps the enzyme to translocate into the nucleus. Since the yield of recombinant TAT-Cre is limited by formation of inclusion bodies, we hypothesized that the positively charged arginine-rich TAT sequence causes the inclusion body formation, whereas its neutralization by the addition of a negatively charged sequence improves solubility of the protein. To prove this, we neutralized the positively charged TAT sequence by proximally attaching a negatively charged poly-glutamate (E12) sequence. We found that the E12 tag improved the solubility and yield of E12-TAT-NLS-Cre (E12-TAT-Cre) compared with those of TAT-NLS-Cre (TAT-Cre) when expressed in E. coli. Furthermore, the growth of cells expressing E12-TAT-Cre was increased compared with that of the cells expressing TAT-Cre. Efficacy of the purified TAT-Cre was confirmed by a recombination test on a floxed plasmid in a cell-free system and 293 FT cells. Taken together, our results suggest that attachment of the E12 sequence to TAT-Cre improves its solubility during expression in E. coli (possibly by neutralizing the ionic-charge effects of the TAT sequence) and consequently increases the yield. This method can be applied to the production of transducible proteins for research and therapeutic purposes.

• Journal of Life Science
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• v.20 no.1
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• pp.103-112
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• 2010

Pemetrexed has demonstrated clinical activity in non-small cell lung cancer (NSCLC) as well as other solid tumors. It transports into the cells via reduced folate carrier (RFC) and is polyglutamated by folypolyglutamate synthetase (FPGS). Pemetrexed directly inhibits several folate-dependent enzymes such as thymidylate synthase (TS), dihydrofolate reductase (DHFR), and glycinamide ribonucleotide formyltransferase (GARFT). We investigated the effects of genetic variations and the expression of RFC, FPGS, TS and DHFR enzymes on drug sensitivity to pemetrexed in NSCLC cells. Polymorphisms in RFC, FPGS, and DHFR were genotyped in four NSCLC cells - A549, PC14, HCC-1588, and H226. Real-time RT-PCR and Western blot was performed to evaluate mRNA transcripts and protein of these genes. The cytotoxicity of pemetrexed was measured by SRB assay. In PC14 and H226 cells, increased mRNA expressions of RFC and FPGS were associated with higher cytotoxicity to pemetrexed. 2R/2R genotype of TS and its increased mRNA expression were associated with drug resistance to pemetrexed in A549 cells, whereas 3R/3R genotype in TS with decreased mRNA expression was associated with higher sensitivity in H226 cells. After pemetrexed treatment, an inverse change of DHFR mRNA and protein expression was found. The strongest linkage disequilibrium (LD) was discovered between-1726C>T and -1188A>C SNP of DHFR gene. Our findings suggest the cytotoxic effect of pemetrexed may be associated with genetic polymorphisms and the expression level of genes involved in pemetrexed metabolisms in NSCLC cells.