• Biomolecules & Therapeutics
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• 제12권2호
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• pp.108-113
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• 2004

This study was performed to investigate the regulatory mechanism of cerebral blood flow of adenosine $A_{2B}$ receptor agonist in the rats, and to define whether its mechanism is mediated by adenylate cyclase and guanylate cyclase. in pentobarbital-anesthetized, pentobrabital-paralyzed and artificially ventilated male Sprague-Dawley rats, all drugs were applied topically to the cerebral cortex. Blood How from cerebral cortex was measured using laser-Doppler flowmetry. Topical application of an adenosine $A_{2B}$ receptor agonist, 5'-N-ethylcar-boxamidoadenosine (NECA; 4 umol/l) increased cerebral blood flow. This effect of NECA (4 umol/l) was not blocked by pretreatment with adenylate cyclase inhibitor, MDL-12330 (20 umol/l). But effect of NECA (4 umol/l) was blocked by pretreatment with guanylate cyclase inhibitor, LY-83383 (10 umol/l). These results suggest that adenosine $A_{2B}$ receptor increases cerebral blood flow. It seems that this action of adenosine $A_{2B}$ receptor is mediated via the activation of guanylate cyclase in the cerebral cortex of the rats.

• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.144-148
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• 2013

Lycopene cyclase converts lycopene to ${\beta}$-carotene by catalyzing the formation of two beta-rings at each end of the linear carotene structure. This reaction takes place as a two-step reaction in which both sides of of the lycopene molecule are cyclized into ${\beta}$-carotene rings via the monocyclic ${\gamma}$-carotene as an intermediate. The crtY gene coding for lycopene cyclase from Paracoccus haeundaensis consists of 1,158 base pairs encoding 386 amino acids residues. An expression plasmid containing the crtY gene (pET44a-CrtY) was constructed and expressed in Escherichia coli, and produced a recombinant protein of approximately 43 kDa, corresponding to the molecular mass of lycopene cyclase. The expressed protein was purified to homogeneity by His-tag affinity chromatography and showed enzymatic activity corresponding to lycopene cyclase. We also determined the lycopene substrate specificity and NADPH cofactor requirements of the purified protein. The $K_m$ values for lycopene and NADPH were 3.5 ${\mu}M$ and 2 mM, respectively. The results obtained from this study will provide a wider base of knowledge on the enzyme characterization of lycopene cyclase at the molecular level.

• Journal of Ginseng Research
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• 제7권2호
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• pp.95-101
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• 1983

The effect of ginsenosides on the adenylate cyclase and guanylate cyclase of rat brain has been studied. We have found that Rbl, Rc and one unknown ginsenoside (probably Ra) exerted reciprocal effects on adenylate cyclase and guanylate cyclase. This dual effect of ginsenosides leads us to speculate that some ginsenosides may act as regulatory agents and modulate the activities of these two enzyme systems.

• 생명과학회지
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• 제10권1호
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• pp.107-113
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• 2000

UV-B와 도열병병원균 접종들의 환경 스트레스에 의한 벼의 POD, SOD및 Diterpene cyclase등의 활성 변화를 조사하여 해 본 결과, 일품벼에서 POD 와 SOD활성이 가장 놓았고, 도열병진전에 따른 PDO활성은 감수성 품종인 일품과 화성은 증가하였으나 저항성 품종인 다산은 감소하였다. 키토산 처리에의한 SOD의 활성 변화는 처리 농도가 높을수록 증가하였다. 키토산 처리후 14일에서의 감수성품종인 화성의 SOD활성은 무처리 식물체에 비하여 높았다. UV-B조사 시간이 길수록 감수성품종인 일폼의 POD활성은 감소하였고, 저항성 품종인 다산은 증가하였다. 특히UV-B의 조사시간에 따른 다산의 POD활성은 차가 없었으나, 화성의 활성은 40분 조사처리시 2배 놓았다 UV-B처리에 비해 p.oryzae를 접종시는 diterpene cyclase의 활성이 놓아졌으며, 병원균 접종후 5일까지 효소활성이 검진적으로 증가하였다.

• 한국자원식물학회지
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• 제21권2호
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• pp.139-143
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• 2008

다섯 종류의 가지과 식물을 대상으로 elicitor에 의해 생합성 되는 capsidiol의 함량을 측정하고 생합성에 관련된 P450 효소의 활성과 관련 유전자 발현을 조사하였다. 고추, 피망 및 담배는 capsidiol의 생합성에 관련된 두개의 유전자인 cyclase와 P450 유전자가 세포내에 존재하였고, elicitor의 처리에 의하여 유전자의 발현이 유도되고 효소의 촉매가 이루어 졌다. 가지세포에는 두개의 유전자가 게놈상에 존재하지만 P450 유전자는 발현되나, cyclase 유전자의 발현은 나타나지 않았다. 감자에는 capsidiol의 생합성에 관련된 P450 및 cyclase 유전자 모두가 존재하지 않은 것으로 나타났다. 본 실험에 사용된 P450과 cyclase 유전자는 식물이 정상상태에 있을 때는 전혀 발현되지 않으나 elicitor에 의해 특이적으로 유도 되는 특징을 보였고, 식물체 조직이나 기관별로 다양한 발현 양상을 보였다.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.96-96
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• 2002

We examined the role of SR 144528 (N-[-(1S-endo-1,3,,3-trimethyl-bicycle[2, 2, 1 ] heptan-2-y1]-5-(-4-chloro-3-mothyl-phenyl)-(4-methylbenzyl)-pyrazole-3- carboxamide) in the modulation of certain AC isoforms in transiently transfected COS-7 cells. We found that CB2 in COS cells has a constitutive activity, and thus leading to inhibition of AC-V activity even in the absence of agonist. In addition, this constitutive modulation of AC is reversed by SR144528. It is now well established that several G protein-coupled receptors can signal without agonist stimulation(constitutive receptors). Inverse agonists have been shown to inhibit the activity of such constitutive G protein-coupled receptor signaling. Agonist activation of the G$\_$i/o/-coupled peripheral cannabinoid receptor CB2 normally inhibits adenylyl cyclase type V and stimulates adenylyl cyclase type II. Using transfected COS cells, we show here that application of SR144528, an inverse agonist of CB2, leads to a reverse action (stimulation of adenylyl cyclase V and inhibition of adenylyl cyclase II). This inverse agonism of SR144528 is dependent on the temperature, as well as on the concentration of the cDNA of CB2 transfected. Pertussis toxin blocked the regulation of adenylyl cyclase activity by SR 144528.

• 식물조직배양학회지
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• 제24권5호
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• pp.273-277
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• 1997

Rhizoctonia solani 추출물(elicitor)을 Hyoscyamus muticus 모상근배양에 처리하였을 때 sesquiterpene cyclase (SC)가 유도됨과 동시에 sesquiterpene화합물이 합성되어 배양액속에 축적하는 것으로 나타났다. 24시간 배양기간 동안 배양액으로부터 sesquiterpene을 추출ㆍ분리하여 배양할 경우, 추출ㆍ분리하지 않은 모상근배양보다 거의 두배의 함량이 생성되었다. Cyclase monoclonal antibody을 이용하여 immunoblot을 시도한 결과, 추출한 모상근배양과 추출하지 많은 모상근배양에서의 SC 절대량은 동일한 것으로 나타났으며, 효소활성도 현저한 차이가 없는 것으로 측정되었다. 이러한 결과는 terpenoid pathway에서 sesquiterpene 생합성이 이용가능한 기질의 량에 의해 조절되는 것으로 사료되며, feedback 조절은 sesquiterpene cyclase 효소에 앞서 일어나는 것으로 추정된다.

• Biomolecules & Therapeutics
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• 제13권2호
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• pp.95-100
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• 2005

This study was performed to investigate the mechanism of cerebral blood flow of adenosine $A_{2B}$ receptor agonist in the rats, and to define whether its mechanism is mediated by nitric oxide (NO) and guanylate cyclase. In pentobarbital-anesthetized, pancuronium-paralyzed and artificially ventilated male Sprague-Dawley rats, all drugs were applied topically to the cerebral cortex. Blood flow from cerebral cortex was measured using laser-doppler flowmetry. Topical application of an adenosine $A_{2B}$ receptor agonist, 5'-N-ethylcar-boxamidoadenosine (NECA; $4{\mu}mol/l$) increased cerebral blood flow. This effect of NECA ($4{\mu}mol/l$) was blocked by pretreatment with NO synthase inhibitor, $N^G$-nitro-L-argine methvlester (L-NAME; $40{\mu}mol/l$) and guanylate cyclase inhibitor, LY-83,583 ($10{\mu}mol/l$). These results suggest that adenosine $A_{2B}$ receptor increases cerebral blood flow. It seems that this action of adenosine $A_{2B}$ receptor is mediated via the NO and the activation of guanylate cyclase in the cerebral cortex of the rats.

• 식물조직배양학회지
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• 제25권3호
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• pp.141-146
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• 1998

[$^3$H] 5-epi-aristolochene (5-EAS)를 담배 현탁배양세포에 투여하여 elicitor에 의해 유도된 세포가 생합성하여 배지로 방출하는 [$^3$H]-capsidiol의 량을 측정함으로써 5-EAS hydroxylase의 활성을 검정하였고, 이 반응의 전 단계에 관여하는 효소인 sesquiterpene cyclase의 발현특성과 비교하였다. 5-EAS hydroxylase는 정상세포에는 전혀 활성을 보이지 않으나 elicitor로써 cellulase를 처리한 세포는 9시간 후부터 유도를 시작하여 18시간 후에 최대 활성을 보였는데 동일한 세포내에서 유도되는 cyclase와 유사한 패턴을 보였다. Cyt P450계 효소의 특이적 억제제로 알려진 ancymidol과 ketoconazole에 의해 5-EAS hydroxylase의 활성은 강한 억제를 보인 반면 cyclase의 활성은 억제를 보이지 않아 5-EAS hydroxylase가 P450계 효소임이 시사되었다.

• Animal cells and systems
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• 제2권2호
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• pp.243-248
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• 1998

We have partially sequenced glutaminyl cyclases from several mammalian and one avian species and found that the two cysteine residues of the human glutaminyl cyclase are completely conserved. The mammalian glutaminyl cyclase has been reported to possess reactive thiols (Busby, Jr, et aI., 1987, J BioI Chern 262, 8532-8536). Mutagenesis of these cysteine residues, however, resulted in only a slight decrease in enzyme activity. Likewise, the recombinant human enzyme was completely resistant to attempted chemical modification of the putative reactive thiols. Although the human glutaminyl cyclase did not appear to have reactive thiols, it was sensitive to diethylpyrocarbonate and acetylimidazole, indicating the presence of functionally important histidine and tyrosine residues which could act as acid/base catalysts. Almost identical deuterium solvent isotope effect (1.2 vs 1.3) upon the reaction by the human and papaya enzymes, respectively, provides an evidence both animal and plant glutaminyl cyclases catalyze pyroglutamyl-peptide formation by intramolecular cyclization.