• 대한미생물학회지
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• 제34권6호
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• pp.533-542
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• 1999

H. pylori produces urease abundantly amounting to 6% of total protein of bacterial mass. Urease genes are composed of a cluster of 9 genes of ureC, ureD, ureA, ureB, ureI, ureE, ureF, ureG, ureH. Production of H. pylori urease in E. coli was studied with genetic cotransformation. Structural genes ureA and ureB produce urease apoprotein in E. coli but the apoprotein has no enzymatic activity. ureC and ureD do not affect urease production nor enzyme activity ureF, ureG, and ureH are essential to produce the catalytically active H. pylori urease of structural genes (ureA and ureB) in E.coli. The kinetics of activation of H. pylori urease apoprotein were examined to understand the production of active H. pylori urease. Activation of H. pylori urease apoprotein, pH dependency, reversibility of $CO_2$ binding, irreversibility of $CO_2$ and $Ni^{2+}$ incorporation, and $CO_2$ dependency of initial rate of urease activity have been observed in vitro. The intrinsic reactivity (ko) for carbamylation of urease apoprotein co expressed with accessory genes was 17-fold greater than that of urease apoprotein expressed without accessory genes. It is concluded that accessory genes function in maximizing the carbamylating deprotonated ${\varepsilon}$-amino group of Lys 219 of urease B subunit and metallocenter of urease apoprotein is supposed to be assembled by reaction of a deprotonated protein side chain with an activating $CO_2$ molecule to generate ligands that facilitate productive nickel binding.

• Journal of Nutrition and Health
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• 제23권3호
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• pp.157-169
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• 1990

$\omega$-3계 지방산의 함량이 많은 어유는 혈청지질을 저하시키고, $\omega$-6계의 arachidonic acid로 부터 thromboxane $A_2$ 및 prostagtandin I$_2$의 생성을 억제하며 동시에 $\omega$-3계의 eicosapentaenoic acid로 부터 thromboxane $A_3$ 및 prostagrandin I$_3$를 소량 합성하므로 동맥경화증의 위험을 감소시킨다고 보고 되어 있다. 그러나, 어유의 효과가 식이중 지방함량이 낮은 수준에서 더 현저한가에 대해서는 확실히 알려져 있지 않다. 본 연구는 서양인과 식사내용이 다르며 또한 관상동맥성 심장질환의 예견 인자가 다른 한국인에 있어서 1일 9g, 12g 및 15g의 어유를 1주간 투여한 후 혈청 apoprotein 및 혈소판기능을 조사하여 동맥경화증 및 관상동맥성 심장질환의 예방식이로서 어유섭취의 효과를 알아보고자 계획되었다. 실험대상은 단체생활을 하는 건강한 여대생으로 평균연령은 21세(20~22세), 평균신장은 160.4cm(158~166cm), 평균체중은 53.4(46~58.5kg)이었으며 실험군은 3군으로 나누어서 한 군에 6명씩 총 18명을 실험대상으로 하였다. 각 실험군에 따라 1일 각각 9g, 12g 및 15g의 어유를 1주간 투여하였다. 일차 실험은 어유투여 전과 각 실험군에 따라 일정량의 어유를 1주간 투여한 직후, 어유투여를 중한한 1주째 및 3주째에 채혈하여 각각 점사를 실시하였다. 이차실험은 일차실험 종료후 6주간의 자유식사를 달리하여 동일한 방법으로 채혈하여서 혈청 apoprotein, 혈소판 기능검사 및 출혈시간을 조사한 결과는 다음과 같다. apoA는 어유투여후 15g군에서 어유투여직후 유의적인 감소(p<0.05>를 나타내었다. apoB는 어유투여 후 유의적인 변화를 나타내지 않았다. 혈소판 수는 어유투여후 감소하는 경향을 보였으며 형소판 부착능은 어유투여 후 감소하는 경향을 보였으나, 유의적인 감소(p<0.05)는 어유 15g 투여군에서 투여 중단 1주째에 나타났다. 혈소판 응집능은 감소하는 경향을 보였으나 유의적인 감소(P<0.01)는 어유 15g 투여군에서 투여 직후에 유의적인 감소(p<0.01)를 나타내었다. Bleeding Time은 길어지는 경향을 보였으나 유의적인 변화(p<0.05)는 어유투여 중단 3주째에 나타났다. 각 기간에 있어서 투여한 어유의 양에 따른 혈청 apoprotein 함량 및 혈소판 기능의 유의적인 차이는 나타나지 않았다.

• Bulletin of the Korean Chemical Society
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• 제11권2호
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• pp.131-134
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• 1990

Cytochrome c induces fusion of phosphatidylserine /phosphatidylethanolamine vesicles while apocytochrome c does not have a fusogenic capability despite the fact that the apoprotein binds to the vesicles more extensively. In order to see whether the difference in the fusogenic behavior comes from the topological variation in membrane bound proteins, the holoprotein and apoprotein were labeled with phenylisothiocyanate, a hydrophobic label, in the presence of its hydrophilic analogue p-sulfophenylisothiocyanate. Apocytochrome c was labeled with the hydrophobic probe more extensively than the cytochrome c, indicating that the apoprotein penetrates deeper into the bilayer than cytochrome c does. The translocation experiments of these proteins by trypsin entrapped vesicles further supported this conclusion.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2679-2683
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• 2015

Background: Phenethyl isothiocyanate (PEITC), the most comprehensively studied aromatic isothiocyanate, has been shown to act as an anti-cancer agent mainly through modulation of biotransformation enzymes responsible for metabolizing carcinogens in the human body. Humans are often exposed to carcinogenic factors, some of which through the diet, such as polycyclic aromatic hydrocarbon benzo[a]pyrene via the consumption of over-cooked meats. Inhibition of the enzymes responsible for the bioactivation of this carcinogen, for example CYP1A1, the major enzyme required for polycyclic aromatic hydrocarbons (PAHs) bioactivation, is recognized as a chemoprevention strategy. Objective: To evaluate the inhibitory effects of PEITC against benzo[a]pyrene-induced rise in rat liver CYP1A1 mRNA and apoprotein levels. Materials and Methods: Precision cut rat liver slices were treated with benzo[a]pyrene at 1 and $5{\mu}M$ in the presence of PEITC ($1-25{\mu}M$) for 24 hours, followed by determination of CYP1A1 mRNA and apoprotein levels using quantitative polymerase chain reaction and immunoblotting. Results: Findings revealed that PEITC inhibited benzo[a]pyrene-induced rise in rat liver CYP1A1 mRNA in a dose-dependent manner as well as the apoprotein levels of CYP1A. Conclusions: It was demonstrated that PEITC can directly inhibit the bioactivation of benzo[a]pyrene, indicating chemopreventive potential.

• Molecules and Cells
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• 제20권3호
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• pp.371-377
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• 2005

The roles that accessory gene products play in activating the Helicobacter pylori urease apoprotein were examined. The activity of the urease apoprotein increased in the following order when it was expressed with the accessory genes: ureG < ureGH < ureFGH < ureEFGH < ureIEFGH. Moreover, stepwise additions of ureE and ureI to ureFGH significantly increased urease activity. Urease apoproteins coexpressed with ureFGH, ureEFGH, and ureIEFGH had similar low chymotrypsin susceptibilities. In vivo and in vitro activation studies showed that the cooperative effect of the accessory proteins involved processes in which the UreFGH complex, UreE, and UreI were implicated. Thus, the UreFGH complex may serve to alter the conformation of the apoprotein into one that is more competent to assemble a stable metallocenter, and that facilitates cooperative effects.

• Journal of Photoscience
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• 제9권2호
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• pp.90-93
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• 2002

Phytochrome A (phyA) and phytochrome B (phyB) perceive light and adapt to fluctuating circumstances by different manners in terms of effective wavelengths, required fluence and photoreversibility. Action spectra for induction of seed germination and inhibition of hypocotyl elongation using phytochrome mutants of Arabidopsis showed major difference. PhyA is the principal photoreceptor for the very low fluence responses and the far-red light-induced high irradiance responses, while phyB controls low fluence response in a red/far-red reversible mode. The structural requirement of their bilin chromophores for photosensory specificity of phyA and phyB was investigated by reconstituting holophytochromes through feeding various synthetic bilins to the following chromophore-deficient mutants: hy1, hyl/phyA and hyl/phyB mutants of Arabidopsis. We found that the vinyl side-chain of the D-ring in phytochromobilin interacts with phyA apoprotein. This interaction plays a direct role in mediating the specific photosensory function of phyA. The ethyl side-chain of the D-ring in phycocyanobilin fails to interact with phyA apoprotein, therefore, phyA specific photosensory function is not observed. In contrast, both phytochromobilin and phycocyanobilin interact with phyB apoprotein and induce phyB specific photosensory functions. Structural requirements of the apoproteins and the chromophores for the specific photoperception of phyA and phyB are discussed.

• 한국영양학회:학술대회논문집
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• 한국영양학회 1997년도 춘계학술대회 초록
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• pp.47-47
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• 1997

• Bulletin of the Korean Chemical Society
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• 제9권4호
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• pp.202-206
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• 1988

In order to investigate the oligomerization state of the plasma membrane proteolipid apoprotein purified from the bovine kidney, fluorescence polarization experiment was carried out in the two different solvent systems, i.e., water and organic solvent(chloroform-methanol). The molecular volumes of the proteins estimated from the Perrin equation, were to be 45,258$A^3$ and 17,608$A^3$ in water and organic solvent, respectively. These values indicate that a trimerization is possibly occurring in the aqueous environment. As an auxiliary experiment for the calculation of the molecular volume using Perrin equation, fluorescence quenching constants ($K_q$) with the quencher acrylamide and fluorescence lifetimes (${\tau}_F$) of the intrinsic fluorophore tryptophan residue were estimated in the two different solvent systems. $K_q$ in water was 18.21$M^{-1}$ and it was 46.24$M^{-1}$ in organic solvent. Fluorescence lifetimes of tryptophan residue were calculated to be 2.80 nsec. in water and 3.81 nsec. in organic solvent, respectively.

• Bulletin of the Korean Chemical Society
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• 제6권5호
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• pp.300-303
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• 1985

To understand the nature of the linkage between chromophore and apoprotein in the photoreceptor of Stentor coeruleus, a conformational analysis has been carried out on the dipeptide amides linked to the chromophore hypericin using an empirical potential function. The conformational energies for the dipeptide amides of Glu (OHyp)-X-NHMe, where X = Leu, Phe, Asp, and Tyr, have been calculated to investigate the influence of peptide residues in stabilizing conformers. It was found that the increase of acidity of hypericin upon photoexcitation may be facilitated by the formation of intramolecular hydrogen bonds between hydroxyl groups of hypericin and carbonyl groups of peptide backbone, and that the stabilities of dipeptide amides do not significantly depend on peptide residues directly linked to chromophore.

• 생명과학회지
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• 제5권4호
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• pp.170-180
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• 1995

A carotennnoprotein from the skin of Ascidian(Halocynthia roretzi) was extracted by Triton X-100 and purified by ammonium sulfate fraction, SephadexG-200 charomatography and DEAE-cellulose ion exchange chromatography. The carotenoprotein was redwith broad $\lambda$$_{max}$ between 495, 467 and 318nm. The red carotenoprotein had an approximate molecular weight of 326KDa(gel filtration). SDS-PAGE indicated the presence of two polypeptodes of 84.1KDa and 74.4KDa, with different mobility in polyacrylamide gel electrophoresis. In the presence of denaturing agents such as organic solvent aand extreme pH, the red complex readily disociates to liberate the yellow carotenoid($\lambda$$_{max}$ 452nm) and a colourless apoprotein. The amino acid composition of carotenoprotein were mainly threonine(15.2%), aspartic acid(12.2%), glutamic acid(11.9%) and serine(9.6%), while proline was not found. The carotenoprotein consisted of lipids as structure units. Its major fatty acids composion were C$_{18:1}$, C$_{16:1}$, and C$_{16:0}$. The monounsaturated fatty acids(41.5%) contained abundant content compared to other fatty aacids(polyunsaturated fatty acids 37.4%, saturated fatty acids 20.6%).