• Journal of Microbiology and Biotechnology
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• 제31권3호
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• pp.464-474
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• 2021

Bacterial cytochrome P450 (CYP) enzymes are responsible for the hydroxylation of diverse endogenous substances with a heme molecule used as a cofactor. This study characterized two CYP154C3 proteins from Streptomyces sp. W2061 (CYP154C3-1) and Streptomyces sp. KCCM40643 (CYP154C3-2). The enzymatic activity assays of both CYPs conducted using heterologous redox partners' putidaredoxin and putidaredoxin reductase showed substrate flexibility with different steroids and exhibited interesting product formation patterns. The enzymatic characterization revealed good activity over a pH range of 7.0 to 7.8 and the optimal temperature range for activity was 30 to 37℃. The major product was the C16-hydroxylated product and the kinetic profiles and patterns of the generated hydroxylated products differed between the two enzymes. Both enzymes showed a higher affinity toward progesterone, with CYP154C3-1 demonstrating slightly higher activity than CYP154C3-2 for most of the substrates. Oxidizing agents (diacetoxyiodo) benzene (PIDA) and hydrogen peroxide (H2O2) were also utilized to actively support the redox reactions, with optimum conversion achieved at concentrations of 3 mM and 65 mM, respectively. The oxidizing agents affected the product distribution, influencing the type and selectivity of the CYP-catalyzed reaction. Additionally, CYP154C3s also catalyzed the C-C bond cleavage of steroids. Therefore, CYP154C3s may be a good candidate for the production of modified steroids for various biological uses.

• 한국미생물·생명공학회지
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• 제18권5호
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• pp.484-489
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• 1990

Bacillus subtilis의 세포내 이눌라아제가 부분정제되고 그의 작용 모드와 일반적 특성이 조사되었다. 이 효소는 gel filtration에 의하여 분자량을 추정하였을 때 49,000이었고, 등진점은 5.2 이었다. 기질에 대한 친화성의 지표인 Km값은 설탕에 대해서는 10mM, 라피노오스에 대해서는 18mM 이었다. 이 효소는 산성쪽에서는 불안정한 단백질로서 pH6.6에서 최대 활성을 보였으며 최적온도는 10분간 반응시켰을 때 50'C였다. 이 효소의 작용모든는 이눌린같은 구조를 가지는 과당 중합체를 과당 끝부분으로부터 하나씩 잘라가는 exo-cleavage 형이었다.

• 한국가축번식학회지
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• 제12권2호
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• pp.120-124
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• 1988

Rat oocyte-cumulus complexes were cultured in verious media in order to induce maturation division in vitro. When the complexes were cultured in mKRB containing estrous rat serum (ERS) and FCS of 5% instead of BSA higher proportions(83.3 and 86.7%) of oocytes matured to metaphase II in 20h compared to control(75%) and t도 maturation rates in mKRB plus FCS were generally higher than those in mKRB plus ERS. Fertilization and early cleavage rates in vitro of the intact oocytes matured in mKRB containing BSA and FCS were generally higher than those of cumulus-removed oocytes and these rates were higher in mKRB containing 5% FCS than those in mKRB containing BSA. These results indicate that maturation rate in vitro was greatly increased by the addition of FCS instead of BSA to mKRB solution and the presence of cumulus cells around oocytes prior to sperm insemintion may be responsible for the increase of in vitro fertilization and early cleavage rates.

• 한국미생물·생명공학회지
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• 제24권6호
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• pp.743-748
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• 1996

For the biological treatment of phenolic resin wastewater containing phenol and formaldehyde, a phenol-degrading yeast was isolated from the papermill sludge, and then identified as Candida tropicalis PW-51 according to morphological, physiological and biochemical properties. The strain was able to degrade high phenol concentrations up to 2,000mg/l within 58 hours in batch cultures. Phenol-degrading efficiency by the strain was maximum at the culture conditions of a final concentration of 9 $\times$ 10$^{6}$ cells/ml, 30$\circ$C and pH 7.0. The mean degradation rate of phenol was highest at 45.5mg/l/h in 1,000mg/l phenol from 500mg/l to 2,000mg/l phenol. Because the enzyme activity of catechol 1,2-dioxygenase increased in the course of degradation of phenol, it seems that this strain degrades phenol via the ortho-cleavage of benzene ring. The isolate C. tropicalis PW-51 could be effectively used for the biological treatment of phenolic resin wastewater.

• 한국미생물·생명공학회지
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• 제16권3호
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• pp.199-204
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• 1988

Naphthalene을 유일한 탄소원으로 이용하는 균을 분식 배양과 연속식 배양에 의해서 토양과 폐수로부터 분리하였다. 이 균은 Pseudomonas putida로 동정되었으며, 최적 pH와 온도는 각각 7.0과 3$0^{\circ}C$ 이었다. 분리된 균은 1,5-dihydroxynaphthalene을 naphthalene보다 더욱 잘 이용하였으며 benzoate와 salicylate도 이용하였다. 또한 catechol dl meta-분해경로를 통해서 분해되었으며, ampicillin, chloramphenicol, kanamycin, streptomycin에 대해서 강한 저항성을 지니고 있었으며, naphthalene의 분해에 관여하는 약 110kb 크기의 plasmid를 1개 지니고 있었다.

• 한국수정란이식학회지
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• 제22권2호
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• pp.121-126
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• 2007

본 연구에서 돼지 난포란에서 채취된 난모 세포들을 체외성숙 후 형태적으로 선별하거나 극체 방출란을 선별하여 활성화 처리 후 48시간째에 분할란을 선별할 때 배발달율이 어느정도 향상되는지를 검토하였다. 난모 세포를 48시간 성숙 배양 후 형태적 선별과 극체의 방출 유무를 검사하고, 선별된 난모 세포들을 $16{\sim}18$시간 추가 배양한 후 7% ethanol로 활성화시키고 $5{\mu}g/ml$ cytochalasin B에 5시간 노출 후 PZM-5 배 양액으로 7일간 배양하였으며, 배양 중 4일째 5% FBS를 추가하였다. 48시간 성숙 후 형태적으로 선별하였을 때, 21.9%가 제거되고 78.1%가 선별되었으며, 극체 방출란을 선별하였을 때, 32.1%가 제거되고, 67.9%가 선별되었다. 형태적으로 선별한 난자를 활성화 처리하여 48시간째에 분할율을 검사하였을 때, 15.8%가 분할하지 않았으며, 52.6%가 정상 분할하였고, 31.6%가 과분할하였으며, 극체 방출란을 선별하여 활성화 처리 후 분할율을 검사하였을 때 7.1%가 분할하지 않았으며, 73.1%가 정상 분할하였고, 19.8%가 과분할하였다. 체외 성숙된 난모세포를 형태적으로 선별하고 활성화 처리 후 분할란을 선별하지 않았을 때, 16.7%가 배반포기로 발달하였고, 형태적으로 선별하고 분할란을 추가로 선별해 배양했을 때 31.7%가 배반포기로 발달하였으며, 극체 방출란만을 선별하여 활성화 처리 후 분할란을 선별하지 않았을 때 39.0%가 배반포기로 발달하였고, 극체 선별과 분할란 선별을 하였을 때 배반포기 발달율이 49.0%에 이르렀다. 48시간째 미분할 난자와 정상 분할 난자, 과분할 난자를 배양하였을 때 48시간째 미분할 난자는 배반포기로 발달하지 못했으며, 정상 분할 난자는 42.5%, 과분할 난자는 4.5%가 배반포기로 발달하였다. 분할하는 시기를 활성화처리 후 12시간 간격으로 조사하였을 때 $0{\sim}12$시간 사이에 4.1%가 분할하였고, $12{\sim}24$시간 사이에 68.6%, $24{\sim}36$ 시간 사이에 19.1%, $36{\sim}48$시간 사이에 2.3%, 48시간까지 미분할 난자가 5.9%였으며, $0{\sim}12$시간 사이에 분할한 난자나 $36{\sim}48$시간 사이에 분할한 난자에서 배반포기로 발달한 난자는 없었으며, $12{\sim}24$시간 사이에 분할한 난자의 39.1%, $24{\sim}36$시간 사이에 분할한 난자의 9.5%가 배반포기로 발달하였다. 이상의 결과로 극체 방출란만을 선별하여 $12{\sim}36$시간 사이에 분할하는 난자들만을 선별하여 배양한다면 배발생능을 가진 난자들의 비율을 높일 수 있을 것으로 사료된다.

• Bulletin of the Korean Chemical Society
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• 제6권6호
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• pp.362-366
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• 1985

The hydrogen atom transfer reaction between substituted methane, $CH_3X,$ and its radical, $CH_2X(X=H,F,CH_3,CN,OH\;and\;NH_2$ was studied by MINDO/3 method. The transition state(TS) structure and energy barriers were determined and variation of the transition state and of the reactivity due to the change of X were analyzed based on the potential energy surface characteristics. It was found that the greater the radical stabilization energy. the looser the TS becomes; the TS occurs at about 15% stretch of the C-H bond, which becomes longer as the radical stabilization energy of $CH_2X$ increasers. The intrinsic barrier, ${\Delta}E*_{x.x},$ of the reaction with X was found to increase in the order $H The degree of bond stretch of the C-H bond stretch of the C-H bond at the TS also had the same order indicating that the homolytic bond cleavage of the C-H bond is rate-determining. Orbital interactions at the TS between LUMO of the fragment $C{\ldots}H{\ldots}C$ and the symmetry adapted pair of nonbonding, $n{\pm}(=n_1{\pm}n_2),$ or pi orbitals of the two X atoms were shown to be the dominant contribution in determining tightness or looseness of the TS. The Marcus equation was shown to apply to the MINDO/3 barriers and energy changes of the reaction.

• Bulletin of the Korean Chemical Society
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• 제28권6호
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• pp.917-920
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• 2007

Ketene-forming eliminations from C4H3(S)CH2C(O)O-C6H3-2-X-4-NO2 (1) promoted by R2NH in MeCN have been studied kinetically. The reactions are second-order and exhibit Bronsted β =0.51-0.62 and |βlg|= 0.47-0.53. Hence, an E2 mechanism is evident. The Bronsted β increased from 0.33 to 0.53 and |βlg| remained nearly the same by the change of the base-solvent from Bz(i-Pr)NH/Bz(i-Pr)NH2+ in 70 mol% MeCN(aq) to Bz(i-Pr)NH-MeCN, indicating a change to a more symmetrical transition state with similar extents of Cβ -H and Cα -OAr bond cleavage. When the β-aryl group was changed from thienyl to phenyl in MeCN, the β value increased from 0.53 to 0.73 and |βlg| decreased from 0.53 to 0.43. This indicates that the transition state became skewed toward more Cβ -H bond breaking with less Cα-OAr bond cleavage. Noteworthy is the greater double bond stabilizing ability of the thienyl group in the ketene-forming transition state.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2003년도 제45차 추계학술대회
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• pp.122.2-123
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• 2003

• 대한생식의학회:학술대회논문집
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• 대한불임학회 1999년도 제38차 추계 학술대회
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• pp.109-109
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• 1999