통합 검색 | Korea Science

고인정;오정일
- 생명과학회지
- /
- 제19권7호
- /
- pp.852-858
- /
- 2009
호흡전자전달계의 cytochrome bc$_1$ complex 또는 cytochrome c oxidase가 기능을 하지 않는 Rhodobacter sphaeroides mutant 내에서 pyridine nucleotide[NAD(P)H와 NAD(P)$^+$]의 농도와 redox 상태는 wild type과 비교할 때 큰 변화가 없었다. 높은 산소분압 조건에서 키운 Rhodobacter sphaeroides cbb$_3$ oxidase mutant 내에서 PrrBA two-component system에 의해서 조절되는 puf 오페론의 발현은 pyridine nucleotide나 전자전달계의 ubiquinone/ubiquinol pool의 redox 상태의 변화에 의해 유도된 것이 아니다. R. sphaeroides cytochrome bc$_1$ complex mutant를 이용하여 광합성기구 합성에 대한 cbb$_3$ cytochrome c oxidase의 억제 효과는 ubiquinone/ubiquinol pool의 redox 변화에 의해 간접적으로 일어나는 것이 아님을 증명하였다.
https://doi.org/10.5352/JLS.2009.19.7.852 인용 PDF KSCI

Kim, Ki-Sung
- BMB Reports
- /
- 제28권6호
- /
- pp.533-537
- /
- 1995
The detection with lucigenin under physiological conditions is selective for ${\cdot} O_{2}^{-}$, for it can be accepted that lucigenin indicates actual intramembranal $\cdot O_{2}^{-}- formation$. Lucigenin chemiluminescence (CL) was elicited from the plasma membrane (PM) only by addition of reduced pyridine nucleotide. NADPH was preferred to NADH in PM and hepatocytes. This specificity was masked by $NAD(P)^+$ inhibition. The half maximum rate of CL increase was obtained with 1.5 ${\mu}m$ NADH or 55 ${\mu}m$ NADPH in hepatocytes and 6 ${\mu}m$ NADH or 30 ${\mu}m$ NADPH in plasma membranes. Measurement of these NADPH values required the presence of a NADPH-regenerating system. With NADPH the maximal rate obtained was 10 fold higher than with NADH. NADPH and NADH could produce CL when having access from either side of the membrane. They seemed to react with the identical acceptor because NADH-induced CL was also inhibited by $NADP^+$. The characteristics of ${\cdot}O_{2}^{-}-formation$ produced by pyridine nucleotide will be discussed.
PDF

Kim, Hak-Jung
- BMB Reports
- /
- 제39권2호
- /
- pp.223-227
- /
- 2006
Dihydrolipoamide dehydrogenase (E3) belongs to the pyridine nucleotide-disulfide oxidoreductase family including glutathione reductase and thioredoxin reductase. It catalyzes the reoxidation of dihydrolipoyl moiety of the acyltransferase components of three $\alpha$-keto acid dehydrogenase complexes and of the hydrogen-carrier protein of the glycine cleavage system. Isoleucine-51 of human E3, located near the active disulfide center Cys residues, is highly conserved in most E3s from several sources. To examine the importance of this highly conserved Ile-51 in human E3 function, it was substituted with Ala using site-directed mutagenesis. The mutant was expressed in Escherichia coli and highly purified using an affinity column. Its E3 activity was decreased about 100-fold, indicating that the conservation of the Ile-51 residue in human E3 was very important to the efficient catalytic function of the enzyme. Its altered spectroscopic properties implied that conformational changes could occur in the mutant.
https://doi.org/10.5483/BMBRep.2006.39.2.223 인용 PDF

Kim, Hak-Jung
- BMB Reports
- /
- 제35권4호
- /
- pp.437-441
- /
- 2002
Dihydrolipoamide dehydrogenase (E3) is a member of the pyridine nucleotide-disulfide oxidoreductase family. Thr residues are highly conserved. They are at the active site disulfide-bond regions of most E3s and other oxidoreductases,. The crystal structure of Azotobacter vinelandii E3 suggests that the hydroxyl group of Thr that are involved in the FAD binding interact with the adenosine phosphate of FAD. However, several prokaryotic E3s have Val instead of Thr. To investigate the meaning and importance of the Thr conservation in many E3s, the corresponding residue, Thr-44, in human E3 was substituted to Val by site-directed mutagenesis. The mutant’s E3 activity showed about a 2.2-fold decrease. Its UV-visible and fluorescence spectra indicated that the mutant might have a slightly different microenvironment at the FAD-binding region.
https://doi.org/10.5483/BMBRep.2002.35.4.437 인용 PDF