• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2881-2882
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• 2011

• 대한임상약리학회:학술대회논문집
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• 1996.12a
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• pp.31-31
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• 1996

• Bulletin of the Korean Chemical Society
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• v.25 no.10
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• pp.1457-1458
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• 2004

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.245-248
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• 2009

• The Korean Journal of Mycology
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• v.21 no.1
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• pp.23-27
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• 1993

Ion effects on $11{\alpha}-hydroxylation$ of progesterone and $5{\alpha}-reduction\;of\;11{\alpha}-hydroxyprogesterone$ by Rhizopus nigricans were investigated. Metal ions such as $Cu^{2+},\;Cd^{2+},\;Co^{2+},\;Mn^{2+},\;Zn^{2+},\;Fe^{2+},\;Mg^{2+},\;Fe^{3+}\;and\;Na^+$ reduced the $11{\alpha}-hydroxylation$ activity, while $K^+$ stimulated the same reaction. Enzyme activity for the $5{\alpha}-reduction$ of $11{\alpha}-hydroxyprogesterone$ was increased in the presence of $Fe^{2+},\;Mn^{2+},\;Mg^{2+},\;Co^{2+},\;Zn^{2+},\;Fe^{3+},\;K^+\;and\;Na^+$, whereas it was decreased in the presence of $Cd^{2+}\;and\;Cu^{2+}$. Potassium ion of $10^{-3}\;M\;$ of concentration was found to be effective for the promotion of $11{\alpha}-hydroxylation$. On the other hand, cadmium ion of $10^{-4}\;M$ was proved to suppress the $5{\alpha}-reduction$ reaction. Progesterone is reported to be transformed into $11{\alpha}-hydroxyprogesterone$ which, in turn, is converted further into $11{\alpha}-hydroxy-allopregnane-3$, 20-dione by R. nigricans. From this point of view, the highest yield of $11{\alpha}-hydroxyprogesterone$ could be obtained when potassium ion of $10^{-3}\;M$ was given initially followed by addition of cadmium ion of $10^{-4}\;M$ to limit conversion of 11{\alpha}-hydroxyprogesterone into $11{\alpha}-hydroxy-allopregnane-\;3$, 20-dione.

• Journal of Microbiology and Biotechnology
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• v.21 no.1
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• pp.14-19
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• 2011

A cyclic undecapeptide-family natural product, cyclosporin A (CyA), which is one of the most valuable immunosuppressive drugs, is produced nonribosomally by a multifunctional cyclosporin synthetase enzyme complex in a filamentous fungal strain named Tolypocladium niveum. Previously, structural modifications of cyclosporins such as a regionspecific hydroxylation at the $4^{th}$ N-methyl leucine in a rare actinomycetes called Sebekia benihana were reported to lead to dramatic changes in their bioactive spectra. However, the reason behind this change could not be determined since a system to genetically manipulate S. benihana has not yet been developed. To address this limitation, in this study, we utilized the most commonly practiced gene manipulation techniques including conjugation-based foreign gene transfer-and-expression as well as targeted gene disruption to genetically manipulate S. benihana. Using these optimized genetic manipulation systems, a putative cytochrome P450 hydroxylase (CYP) gene named CYP506, which is involved in CyA hydroxylation in S. benihana, was specifically disrupted and genetically complemented. The S. benihana${\Delta}$CYP506 exhibited a significantly reduced CyA hydroxylation yield as well as considerable yield restoration by functional complementation of the S. benihana CYP506 gene, suggesting that the genetically manipulated S. benihana CYP mutant strains may serve as a more efficient bioconversion host for various valuable metabolites including CyA.

• The Korean Journal of Mycology
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• v.18 no.2
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• pp.84-88
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• 1990

Hydroxylation in the $11{\alpha}$-position of progesterone molecules was carried out using Rhizopus nigricans spores immobilized within various gel matrices, among which polyacrylamide and agar gel were proved to be the most effective. Reactions with the immobilized cells and in­tact free cells showed almost identical conversion rate of progesterone, optimal pH and reaction time for attaining maximal yield, from which were confirmed absence of any decay and modification of enzyme activities.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.151-154
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• 2011

Catalytic activity such as conversion and selectivity on the phenol hydroxylation over TS-1 prepared by hydrothermal method and microwave heating method, respectively, was compared and discussed for understanding the dependence of solvent such as water, methanol, acetone, respectively, during phenol hydroxylation, with hydrogen peroxide. Basic physical properties such as XRD, EDS, SEM and $N_{2}$ adsorption/desorption were determined and compared. The relationship between catalytic activity and physical properties of TS-1 was explained.

• Journal of Nutrition and Health
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• v.12 no.1
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• pp.9-16
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• 1979

Cholecalciferol은 피하에서 자외선과 체온의 작용을 받아 7-dehydrocholesterol로부터 Previtamin D를 거쳐 합성이 되며 이어서 간에 빨리 축적, 25 hydroxylation을 거치게 되고 신장에서 가장 활성을 띤 형태인 $1.25-(OH)_{2}CC$로 변하게 된다. 한편 신장에서는 체내의 Ca, P이 정상으로 존재하게 되면 1-hydroxylation이 억제되는 대신 24-hydroxylation이 일어나 또 다른 active form인 $24,\;25-(OH)_{2}CC$가 되는데 24-hydroxylation의 역활이 무엇인가에 대해서는 아직 구체적으로 밝혀지지 않았다. $24,\;25-(OH)_{2}CC$나 $1.25-(OH)_{2}CC$는 모두 공통적으로 또 다른 active form인 $1.24,\;25-(OH)_{3}CC$를 형성할 수도 있다. 그중 $1.25-(OH)_{2}CC$는 Steroid H.으로 일컬어지기도 하는 Vit. D metabolite중에서 가장 활성을 가진 형태이며 표적기관으로 크게 소장, 뼈, 신장을 들 수 있다. 소장에서의 역활은 무엇보다도 Ca흡수에 관련되는 것으로 소장에서의 Ca흡수와 Ca BP합성에 관여한다. 골격 형성과 뼈의 mineralization에 관여하는 Vit. D metabolite를의 효과에 관해서는 아직까지 일관성있는 보고가 없다. 한편 $1.25-(OH)_{2}CC$는 side chain oxidation을 거쳐 $CO_{2}$와 미지의 물질을 생성하는데 이 mechanism이 어떤 의미를 갖는지는 분명치 않다. 그밖에 또 다른 표적기관으로서 최근 타액선의 존재가 알려졌으며 Vit. D가 배설되는 경로에 대해서는 새로운 바가 없다. Vit. D가 담즙을 통해서 우선적으로 배설되고 소량이 뇨를 통해 배설되는데 metabolite들의 배설경로는 더욱 규명되어야 할 과제이다.

• The Korean Journal of Mycology
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• v.15 no.1
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• pp.23-28
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• 1987

Physicochemical factors influencing the $11{\alpha}$, hydroxylation of progesterone by Rhizopus nigricans Ehrenberg were studied. The higher is the concentration of progesterone. the shorter time is need to attain maximum yield in the $11{\alpha}-hydroxyprogesterone$. High concentration in progesterone was supposed to inhibit the hydroxylation reaction of the $11{\alpha}-hydroxyprogesterone$. The range of optimum pH and temperature appeared to be rather broad and these conditions were similar to those of optimum growth of the mycelia. Agitation at a higher speed than a certain limit, and the presence of sugars accelerated the $11{\alpha}-hydroxyprogesterone$ reaction. Glucose was found to be more effective for the reaction using spores rather than mycelia as enzyme sources. Organic solvents were proved to supress the enzyme activity, which decreased with increase in the concentration of the organic solvents and in the time for pretreatment with the solvents.