• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1507-1514
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• 2008

Cholesterol oxidase catalyses the conversion of cholesterol to 4-cholesten-3-one. This enzyme has been used for clinical assay of human serum cholesterol and for reduction of cholesterol level in foods and feeds. In order to search the microorganism which has a high extracellular and stable activity of cholesterol oxidase, soil microorganisms were screened. As a result, the one with the highest extracellular cholesterol oxidase activity was obtained and named as the BEN 115. The BEN 115 strain was identified as one of the Nocardia species based on our taxonomic studies. The cholesterol oxidase from this strain was shown to have two bands of extracellular proteins on SDS-PAGE and Western blot. Their molecular masses were estimated to be about 55 and 57 kDa, respectively. In addition, this cholesterol oxidase was considerably stable at the broad range of pH $3.5{\sim}9.5$ and at the temperature of $25{\sim}55^{\circ}C$. The optimum pH and temperature of this cholesterol oxidase were pH 5.5 and $35^{\circ}C$, respectively. The activity of extracellular cholesterol oxidase could be enhanced 1.6 to 2.0 folds by the addition of nonionic detergent such as Triton X-114, Triton X-100, or Tween-80 into the culturing broth. The substrate specificities against campesterol, sitosterol and stigmasterol were measured to be 50%, 50%, and 27%, respectively, compared to the cholesterol. These results suggest that Nocardia sp. BEN 115 may be useful as a microbial source of cholesterol oxidase production.

• Journal of Microbiology
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• v.41 no.4
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• pp.284-288
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• 2003

Bacillus subtilis SFF34 degrading cholesterol was applied to reduce residual cholesterol content in fermented flatfish. When the bacterial cells were inoculated as a start culture, a maximal level (1.7 U/g) of cholesterol oxidase was obtained after 10 days, which was two times higher than that (0.8 U/g) without inoculation. Residual cholesterol contents with and without inoculation of the cells were 0.5 mg/g and 0.8 mg/g after 12 days of fermentation, respectively. Cholesterol derivatives including cholesterol- 5${\alpha},\;6{\alpha}$-epoxide, 4-cholesten-3-one and 7${\beta}$-hydroxycholesterol were detected in raw flatfish as well as fermented flatfish. Campesterol and 25-hydroxycholesterol were detected only after fermentation. However, no significant differences in their contents were observed regardless of inoculation.

• YAKHAK HOEJI
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• v.51 no.6
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• pp.495-499
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• 2007

Seven epoxy- and hydroxyandrostane derivatives ($DH-1{\sim}DH-7$) and nine epoxy- and hydroxycholestane derivatives ($CH-1{\sim}CH-9$) with unsaturation in ring A and ring B were synthesized from DHEA and cholesterol, respectively. The antinociceptive effects of all synthesized compounds were measured by hot plate method. Most of androstane derivatives except $1{\alpha},2{\alpha}$-epoxy-4,6-androstadiene-3,17-dione (DH-3), and CH-6, CH-7 and CH-9 exhibited antinociceptive effect. 1,4-Androstadiene-$3{\beta},17{\beta}$-diol (DH-5, 100 mg/kg, $35.8{\pm}7.39$), $6{\alpha},7{\alpha}$-epoxy-1,4-androstadiene-3,17-dione (DH-4, 100 mg/kg, $32.6{\pm}5.50$) and $5{\alpha},6{\alpha}$-epoxy-17-oxo-androstan-$3{\beta}$-ol (DH-1, 100 mg/kg, $32.5{\pm}2.98$) were more effective than morphine (10 mg/kg, $30.6{\pm}0.5$). The analgesic effects of androstane derivatives on acetic acid writhing in mice were lower than aspirin. The androstane derivatives were less effective than ibuprofen at inhibiting effects on the carrageenin induced paw oedema. 4,6-Cholestadien-$3{\beta}$-ol (CH-5), $1{\alpha},2{\alpha}$-epoxy-4,6-cholestadien-$3{\beta}$-ol (CH-7) and $7{\alpha}$-hydroxy4-cholesten-3-one (CH-9) showed the decrease of serum triglyceride and total cholesterol levels in poloxamer P-407 injected rat.