해녀콩 ( Canavalia Lineate ) 잎에서 부분정제한 Ornithine Carbamoyltransferase 에 관하여

황일두,권영명 ( Il Doo Hwang,Young Myung Kwon ) 생화학분자생물학회 1991 BMB Reports Vol.24 No.6

Ornithine carbamoyltransferase(OCTase) was partially purified and examined subcellular distribution of its activity from leaves of Canavalia lineata to study the role of OCTase in relation to canavanine biosynthesis. The purification steps involved streptomycin sulfate precipitation, ammonium sulfate fractionation, DEAE-Sephacel column chromatography, and Sephacryl S-300 gel chromatography. OCTase was purified 81.7 fold with 6% recovery. Molecular weight of the enzyme was estimated to be 120 kD and the optimum pH was 7.8 in potassium phosphate buffer. The partially purified enzyme produced citrulline from ornithine an carbamoyl phosphate, and also catalyzed canaline and carbamoyl phosphate to ureidohomoserine. The value of K_m for ornithine and canaline were calculated to be 14.1 mM and 5.5 mM respectively with 20 mM carbamoyl phosphate, and K_m for carbamoyl phosphate was 10.6 mM with 20 mM ornithine. The cytosolic fraction (140,000 g supernatant) by differential centrifugation contained 61% of the total OCTase activities. The fraction contained chloroplasts showed a little enzymatic activity (0.8%) after Percoll density gradient centrifugation, while no enzymatic activity was detected at mitochondrial fraction.

해녀콩(Canavalia lineata)잎에서 부분정제한 Ornithine Carbamoyltransferase에 관하여

황일두,권영명,Hwang, Il-Doo,Kwon, Young-Myung 생화학분자생물학회 1991 한국생화학회지 Vol.24 No.6

해녀콩(Canavalia lineata)잎에서 ornithine carbamoyltransferase(OCTase)를 부분정제 하여 canavanine대사와 연관된 일부성질과 효소활성의 세포내 분포를 조사하였다. 이 효소는 황산스트 토마이신 침전, ammonium sulfate 분획, DEAE-Sephacel 이온교환 크로마토그래피, 그리고 Sephacryl S-300 겔 크로마토그래피를 거쳐 정제한 결과 purification fold는 81.7이고 회수율은 6%이었으며 분자량은 120 kD로 산출되었고 활성의 최적 pH는 인산완충액의 경우 7.8이었다. 한편, 이 효소는 ornithine과 carbamoyl phosohate로부터 citrulline을 합성할 뿐만 아니라 canaline과 carbamoyl phosphate를 기지로 이용하여 ureidohomoserine을 합성할 수 있었다. 그리고 20mM carbamoyl phosphate일 때 ornithine에 대한 $K_m$은 14.1 mM이며 canaline에 대한 $K_m$은 5.5 mM이었고, 20mM ornithine일 때 carbamoyl phosphate에 대한 $K_m$은 10.6 mM으로 나타났다. OCTase 활성의 세포내 분포를 분별 원심분리와 Percoll 밀도구배법으로 조사한 결과 효소활성은 시토졸 분획(140,000 g 상등액)에 전체효소활성 중 61%가 집중되었고, 엽록체에서는 활성의 일부가 검출되었으나 미토콘드리아에서는 검출되지 않았다. Ornithine carbamoyltransferase(OCTase) was partially purified and examined subcellular distribution of its activity from leaves of Canavalia lineata to study the role of OCTase in relation to canavanine biosynthesis. The purification steps involved streptomycin sulfate precipitation, ammonium sulfate fractionation, DEAE-Sephacel column chromatography, and Sephacryl S-300 gel chromatography. OCTase was purified 81.7 fold with 6% recovery. Molecular weight of the enzyme was estimated to be 120 kD and the optimum pH was 7.8 in potassium phosphate buffer. The partially purified enzyme produced citrulline from ornithine an carbamoyl phosphate, and also catalyzed canaline and carbamoyl phosphate to ureidohomoserine. The value of $K_m$ for ornithine and canaline were calculated to be 14.1 mM and 5.5 mM respectively with 20 mM carbamoyl phosphate, and $K_m$ for carbamoyl phosphate was 10.6 mM with 20 mM ornithine. The cytosolic fraction (140,000 g supernatant) by differential centrifugation contained 61% of the total OCTase activities. The fraction contained chloroplasts showed a little enzymatic activity (0.8%) after Percoll density gradient centrifugation, while no enzymatic activity was detected at mitochondrial fraction.

유철수 (劉哲秀) 교수 회갑기념호 - 금속 재료공학 ; Cr 피복을 통한 용융탄산염 연료전지용 316L 스테인레스 강의 내식성 향상에 대한 연구

황일두(Il Doo Hwang),김경국(Kyung Kook Kim),김남진(Nam Jin Kim),이덕열(Dok Yol Lee) 고려대학교 공학기술연구소 1997 공학논문집 Vol.34 No.1

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Brassinosteroids in Plant Developmental Signaling Networks

류호진,황일두 한국식물학회 2013 Journal of Plant Biology Vol.56 No.5

Brassinosteroids (BRs) are plant steroid hormoneswith essential roles in a broad range of biological anddevelopmental processes. The molecular components ofcanonical BR signaling pathways, including the plasmamembrane-anchored co-receptor complex (BRI1 and BAK1),cytoplasmic and nuclear signal transmitters (BSK1, CDG1,BSU1, 14-3-3 proteins, BIN2, and PP2A), and key transcriptionfactors (BZR1, BES1, and BEHs) have been well established,and recent studies have revealed the prominent roles ofcrosstalk between BR pathways and other signaling pathwaysin diverse plant developmental processes. We provide anoverview of recent progress in our understanding of thebiological roles of the interplay between BRs and othersignaling cues, with an emphasis on how BRs regulate plantdevelopmental programs by modulating diverse signalingpathways.

고체산화물연료전지 개발 현황

김재육,황일두,이준,김진영 한국세라믹학회 2012 세라미스트 Vol.15 No.3

Plant Hormonal Regulation of Nitrogen-Fixing Nodule Organogenesis

류호진,황일두,조현우,최대석 한국분자세포생물학회 2012 Molecules and cells Vol.34 No.2

Legumes have evolved symbiotic interactions with rhizo-bial bacteria to efficiently utilize nitrogen. Recent pro-gress in symbiosis has revealed several key components of host plants required for nitrogen-fixing nodule organogenesis, in which complicated metabolic and signaling pathways in the host plant are reprogrammed to generate nodules in the cortex upon perception of the rhizobial Nod factor. Following the recognition of Nod factors, plant hormones are likely to be essential throughout nodule organogenesis for integration of developmental and environmental signaling cues into nodule development. Here, we review the molecular events involved in plant hormonal regulation and signaling cross-talk for nitrogen-fixing nodule devel-opment, and discuss how these signaling networks are integrated into Nod factor-mediated signaling during plant-microbe interactions.

316L 스테인리스강의 내식성 코팅에 관한 연구 : Ⅰ. Ni-Al 금속막 코팅 Ⅰ. Ni-Al Metallic Coating

이덕열,김남진,황일두,송석권 대한금속재료학회(대한금속학회) 1997 대한금속·재료학회지 Vol.35 No.9

316L stainless steel plates, which are usually used for metallic components of molten carbonate fuel cells, were coated with nickel and aluminum successively for the enhancement of their corrosion resistance. Electroplating and pack cementation were employed respectively for nickel and aluminum coating. The corrosion property of the coated specimen was checked by dipping test and anodic polarization test, and compared with those of the bare stainless steel and the one coated only with aluminum. In the case of dipping test the specimen was characterized, before and after the test, using optical microscopy to study the morphology of its cross-section, and X-ray diffraction to identify the phases of the coated layer. Intermetallic compound of Al₃Ni₂ was formed on the surface of the coated specimen and this specimen turned out to be highly resistant to corrosion, even more than the one coated only with aluminum.

Phosphorylation Dependent Nucleocytoplasmic Shuttling of BES1 Is a Key Regulatory Event in Brassinosteroid Signaling

류호진,Hyunwoo Cho,김강민,황일두 한국분자세포생물학회 2010 Molecules and cells Vol.29 No.3

Brassinosteroids (BRs) play important roles in plant growth and development. BRs modulate the phosphoryla-tion status of two crucial transcription factors, BRI1 EMS SUPPRESSOR1 (BES1) and BRASSINAZOLE RESISTANT1 (BZR1). Here we show that BES1 functions as a nucleocy-toplasmic signal transmitter, and that its subcellular local-ization modulates the output intensity of the BR signal. BRASSINOSTEROID INSENSITIVE2 (BIN2) and other group II GLYCOGEN SYNTHASE KINASE 3 (GSK3)-like kinases phosphorylate BES1 and induce its nuclear export by regulating its binding affinity with 14-3-3 proteins. We identified twelve putative phosphorylation residues in BES1. Two of these residues, Ser 171 and Thr 175, are critical for interaction with 14-3-3 proteins. The other puta-tive phosphorylation sites in the N-terminal region are required for the BIN2-mediated nuclear export of BES1. Mutations of these motifs result in increased nuclear ac-cumulation of BES1 and enhanced BR responses in trans-genic plants. Taken together, our results indicate that the spatial redistribution of BES1 is important for regulation of the BR signaling output.

Predominant Actions of Cytosolic BSU1 and Nuclear BIN2 Regulate Subcellular Localization of BES1 in Brassinosteroid Signaling

류호진,김강민,Hyunwoo Cho,황일두 한국분자세포생물학회 2010 Molecules and cells Vol.29 No.3

During brassinosteroid (BR) signaling in Arabidopsis, BSU1 (bri1 SUPPRESSOR1) phosphatase and BIN2 (BRASSINOSTEROID INSENSITIVE2) kinase regulate the signal intensity by determining the phosphorylation status of the transcription factors BZR1 (BRASSINAZOLE RESISTANT1) and BES1 (bri1 EMS SUPPRESSOR1). Here, we report that BIN2 and BSU1 are nucleocytoplasmic regu-lators that modulate the subcellular localization of BES1, with differential activities between the nucleus and the cytosol. In our experiments, the nuclear BIN2 induced phosphorylation and nuclear export of BES1 more effi-ciently than cytosolic BIN2. The cytoplasmic BSU1 medi-ated the dephosphorylation and nuclear translocation of BES1 more efficiently than the nuclear one. BSU1 com-promised the dwarf phenotype of bri1-5, a weak allele of BRI1 (BR-INSENSITIVE 1) receptor kinase, more effectively when localized in the cytosol than in the nucleus in trans-genic plants. In conclusion, the predominance of cytosolic BSU1 and nuclear BIN2 might be required for the efficient subcellular localization of BES1 in BR signaling.

MAP Kinase-Mediated Negative Regulation of Symbiotic Nodule Formation in Medicago truncatula

류호진,Carole Laffont,Florian Frugier,황일두 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.1

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cas-cades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula. The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN. We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module sup-presses symbiotic nodule development via the action of early nodulation transcription factors.