• 한국미생물·생명공학회지
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• 제13권4호
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• pp.361-366
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• 1985

여러 가지 속의 세균을 대상으로 5-fluorocytosine deaminase의 생산균과 기질 특이성을 검토한 결과, 5-fluorocytosine deaminase의 생산성은 종, 속에 관계없이 다양하게 나타났으며 기질로서는 cytosine, 5-fluorocytosine, 5-methylcytosine이 모두 이용될 수 있는 것으로 나타났다. 효소 생산균 중에서 비교적 활성이 높다고 인정되는 Xanthomonas campestris IAM 1671의 효소 생산을 위한 배지의 조성은 glycerin 0.5%, peptone 1%, yeast extract 0.5%. NaCl 0.5% (pH 7.0)로 설정하였다. 본 균의 효소 생산은 500$m\ell$용 진탕 flask에 효소생성 최적배지 90$m\ell$를 넣어 3$0^{\circ}C$에서 24시간 배양했을 때 최대로 나타났다.

• 대한미생물학회지
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• 제21권2호
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• pp.271-276
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• 1986

Amphotericin B and rifampin or 5-fluorocytosine were tested for synergism against Candida albicans in a synthetic mdium. The test was based on viability studies in which fungicidal activity was determined during the incubation hours of drug exposure. Concentration of amphotericin B(0.2ug per ml and 0.4ug per ml) in combination with inactive concentration of rifampin(12.5ug per ml) or 5-fluorocytosine(25ug per ml) resulted in rapid decrease of colony froming unit(CFU). On the basis of these and earlier studies, it is concluded that amphotericin Band rifampin or 5-fluorocytosine are synergistic against various yeasts and yeast-like fungi under widely differing experimental conditions.

• 대한미생물학회지
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• 제19권1호
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• pp.35-40
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• 1984

The effectiveness of three antifungal antibiotics amphotericin B, clotrimazole and 5-fluorocytosine was tested against 120 clinical isolated Candida species. The minimum inhibitory concentrations of amphotericin B was considerably lower than those of clotrimazole and 5-fluorocytosine. High-level resistance to 5-fluorocytosine was present in 50% of the isolates. The combination of clotrimazole and 5-fluorocytosine produced synergistic inhibition against all 20 strains of Candida albicans tested that were relatively resistant to both antifungal agents.

• 대한미생물학회지
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• 제21권1호
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• pp.63-71
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• 1986

The antifungal activities of amphotericin B, 5-fluorocytosine, and ketoconazole in combination of amphotericin B/ketoconazole and 5-fluorocytosine/ketoconazole were determined against 42 strains of Candida spp. isolated from oral cavity. Among 42 strains of Candida species, 36 strains of Candida albicans, 2 strains of Candida parapsilosis and Candida tropicalis 1 strain of Candida krusei and Candida stellatoidea were identified. The minimum inhibitory concentrations(MICs) of amphotericin B, 5-fluorocytosine and ketoconazole for these strains were ranged from 0.05-1.56 mcg/ml, 12.5->100.0 mcg/ml and 0.2-50.0 mcg/ml. In all of the experimental strains, amphotericin B had the greatest antifungal activity on a dilution basis. When a microtiter checkerboard technique was used 5-fluorocytosine acted synergistically with ketoconazole against all strains, whereas amphotericin B has a reduced effect. The killing curve experiments with on strain of Candida albicans WMC-85024 demonstrated that the combination of amphotericin B/ketoconazole and 5-fluorocytosine/ketoconazole produced a decrease in number of colony forming unit of >3 logs in 72 hours.

• KSBB Journal
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• 제13권6호
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• pp.669-674
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• 1998

This study was carried out particularly focusing on he antitumor effect in combination with 5-fluorocytosine(5-FC), antifungal agent, and extracellular cytosine deaminase from Chromobacterium violaceum YK 391 against U-937, K-562 and SNU-C4 cells. While the addition of 10$\mu\textrm{g}$/100 ${\mu}\ell$ of anticancer agent, 5-fluorouracil(5-FU), to U-937, K-562 and SNU-C4 caused the decrease of proliferation 90%, 75% and 93% respectively, the addition of 20 $\mu\textrm{g}$/100 ${\mu}\ell$ of the extracellular cytosine deaminase and 10 $\mu\textrm{g}$/100 ${\mu}\ell$ of antifungal agent 5-FC caused the decrease of proliferation 80%, 70% and 90%, respectively. These results, therefore, reveal that this enzyme has the similar clinical effect for considering of adjuvant antitumor effect. From the above results, the treatment of 5-FC and the cytosine deaminase was very effective and showed the possibility to remove side effects which easily occur by the treatment of 5-FU only. An extracellular cytosine deaminase.

• 미생물학회지
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• 제26권3호
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• pp.207-214
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• 1988

A cytosine deaminase from the cell-free extract of an isolate was examined after ethyl alcohol reactionation. The enzyme catalyzed the conversion of 5-fluorocytosine to 5-fluorouracil by the possession of specificity to the substrate. The optimum temperature and storage time on the stability of the enzyme were at below $50^{\circ}C$ and near 2 days in tris-HCl buffer. The maximum activity was also presented ar 9.0 in pH and $45^{\circ}C$ in temperature. The pHs and temperatures for the enzyme activity ranged from 8.5-9.5 and from 40-$50^{\circ}C$, respectively. the presence of $Ag^{+}, Hg^{2+}, Zn^{2+}$ in the reaction mixture resulted in the marked inhibition in the activity, but 1mM of $Fe^{3+}, K^{+}$, or $Na^{+}$ increased the enzyme activity. The enzyme preparation was vot affected by inhibitors used except N-ethylmaleimide of 1 and 10mM, and considerably activated by 1mM of pyrophosphate and 10mM of phosphate.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.150-155
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• 1992

토양 분리 균주로부터 얻은 배양액을 20-80 황산암모늄으로 분획한 후 세포의 cytosine deaminase의 성질을 검토하였다. 이 효소는 cytosine과 5-fluorocytosine(5-FC)에 기질 특이성을 가짐으로서 각각 uracil과 5-fluorouracil(5-FU)로 전환을 촉매하였다. 효소안정성에 대한 온도와 보존기간은 tris-HC1 완충용액에서 검토한 결과 최적온도는 $50^{\circ}C$ 부근이하에서 90 이상의 잔존활성을, 보존시간은 4일정도에서 80 이상의 잔존활성을 유지하였다. 최대 pH 8.0과 $37^{\circ}C$의 온도에서 나타났다. 활성에 적당한 pH는 8.0~8.5였고, 온도는 37~$45^{\circ}C$의 범위였다.

• 대한수의학회지
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• 제22권2호
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• pp.139-147
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• 1982

A total of 133 isolates of yeast-like fungi was tested for sensitivity to seven different antifungal agents. The yeast-like fungi tested were isolated from the milk from normal or mastitic bovine quaters or from bovine feces. They were 5 Candida albicans (C. albicans) isolates, 63 C. krusei, 27 C. tropicalis, 5 C. parapsilosis, 10 Torulopsis glabrata, 6 Rhodotorula sp., 6 Hansenula sp. and 1 Pichia sp. isolate. The antifungal agents tested were nystatin, griseofulvin, cycloheximide, 5-fluorocytosine, miconazol, clotrimazole and tolnaftate. In general, clotrimazole, miconazol and 5-fluorocytosine were more effective in antifungal activity in vitro against the test organisms than the rest of the agents tested. However, some of the isolates showed higher resistance to certain antifungal agents compared to the other isolates of the some species. They were: 1 C. albicans isolate to 5-fluorocytosine; 1 C. albicans to 5-fluorocytosine, miconazol and clotrimazole; 1 C. krusei to 5-fluorocytosine and cycloheximide; and 11 C. tropicalis isolates to cycloheximide. The minimum inhibitory concentrations(MIC) of clotrimazole were $12.5{\mu}g/ml$ or lower for all isolates tested except one C. albicans isolate, for which MIC of the drug was $100{\mu}g/ml$. On the other hand, the MIC's of cycloheximide were $6.5{\mu}g/ml$ or lower for all isolates except the following; all isolates of C. albicans ($100{\mu}g/ml$), C. pseudotropicalis ($200{\mu}g/ml$) and Rhodotorula sp. ($25-50{\mu}g/ml$), 11 C. tropicalis isolates ($100{\mu}g/ml$) and 1 C. krusei isolate ($200{\mu}g/ml$).

• 한국미생물·생명공학회지
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• 제31권3호
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• pp.292-296
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• 2003

The antibacterial effect against cariogenic bacteria was evaluated in combination of 5-FC and intracellular cytosine deaminase from Chromobacterium violaceum YK 391. While S. mutans, L. parabuchneri and A. naeslundii showed antibacterial effect against 10 mM of 5-FU, S. intermedius, S. mitis, S. agalactiae, L. lactis, A. israelii, A. viscosus don't caused antibacterial effect. The addition of the cytosine deaminase and 10 mM of 5-FC to S. mutans, S. sanguis, L. brevis, L. parabuchneri, L. oris and A. naeslundii caused weakly antibacterial effect. S. sanguis caused weakly antibacterial effect against 10 mM of 5-FC. These results suggested that combination of the cytosine deaminase and 5-FC was showed the possibility to precautionary measures of dental caries.

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1182-1189
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• 2004

Cytosine deaminase (cytosine aminohydrolase, EC 3.5.4.1) stoichiometrically catalyzes the hydrolytic deamination of cytosine and 5-fluorocytosine to uracil and 5-fluorouracil, respectively. The intracellular cytosine deaminase from Chromobacterium violaceum YK 391 was purified to apparent homogeneity with 272.9-fold purification with an overall yield of $13.8\%$. The enzyme consisted of dimeric polypeptides of 63 kDa, and the total molecular mass was calculated to be approximately 126 kDa. Besides cytosine, the enzyme deaminated 5-fluorocytosine, cytidine, 6-azacytosine, and 5-methylcytosine, but not 5-azacytosine. Optimum pH and temperature for the enzyme reaction were 7.5 and $30^{\circ}C$, respectively. The enzyme was stable at pH 6.0 to 8.0, and at 30T for a week. About $70\%$ of the enzyme activity was retained at $60^{\circ}C$ for 5 min. The apparent $K_{m}$ values for cytosine, 5-fluorocytosine, and 5-methylcytosine were calculated to be 0.38 mM, 0.87 mM, and 2.32 mM, respectively. The enzyme activity was strongly inhibited by 1 mM $Hg^{2+},\;Zn^{2+},\;Cu^{2+},\;Pb^{2+},\;and\;Fe^{3+}$, and by o-phenanthroline, $\alpha,\;{\alpha}'$-dipyridyl, p-choromercuribenzoate, N-bromosuccinimide, and cWoramine­T. In addition, the enzyme activity was strongly inhibited by I mM 2-thiouracil, and weakly inhibited by 2-thiocytosine, or 5-azacytosine. Finally, intracellular and extracellular cytosine deaminases from Chromobacterium violaceum YK 391 were found to have a different optimum temperature, apparent $K_{m}$ value, and molecular mass.