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o - Phthalaldehyde 를 이용한 아미노산 잔기의 화학변형 반응
이기평 ( Key Pyoung Lee ),김두식 ( Doo Sik Kim ) 생화학분자생물학회 1994 BMB Reports Vol.27 No.2
Imidazole은 o-phthaladedyde 조내하에 일차 아민 화합물로 사용된 glycine과 빠르게 반응하여 강한 형광을 내는 화합물을 생성했다. 이 반응 생성물은 0.1M potassium phosphate Ph7.0 완충용액에서 332㎚의 최대 흡광을 보였으며 332㎚ 자극에 의해 422㎚에서 최대 형광을 나타냈다. Imidaxole 기와 일차 아미노기를 모두 갖고 있는 histidine 역시 같은 반응 조건에서 o-phthaladedyde와 신속하게 반응하여 335㎚의 최대 흡광과 440㎚에서의 최대 형광을 나타냈다. 이 화합물은 25℃에서 수분 이내에 변형되기 시작했으며 그 결과 형광 감소와 함께 최대 흡광이 긴 파장 쪽으로 이동되었다. 반응 산물의 이와 같은 분광학적 특성을 thiol 화합물 존재하에 o-phthaladedyde와 일 아민 화합물이 생성하는 isoindole 유도체의 성질과 잘 일치되는 것이다. 따라서 이들 결과는 thiol 화합물 대신 imidazole이 반응하여 isoindole 유도체가 생성됐음을 보여 주는 것으로써 단백질 구조에서 인접하여 위치하고 있는 lysine의 ε-아미노기와 histidine의 imidazole 기에 대한 cross-link 화학 변형에 이용될 수 있는 새로운 반응임을 제시하였다.
Rhizobium trifolii Malonyl - CoA Synthetase 의 활성자리 구조 연구 Ⅰ: ATP 결합 부위의 화학변형
이기평,김두식 ( Key Pyoung Lee,Doo Sik Kim ) 생화학분자생물학회 1994 BMB Reports Vol.27 No.2
Malonyl-CoA synthetase of Rhizobium trifolii was rapidly and irreversibly inactivated by o-phthalaldehyde at 25℃ (pH7.1). The second-order rate constant for the inactivation was determined to be 2,165M^(-1)min^(-1) and the raction order was 0.92. The inactivation of malonyl-CoA synthetase was completely protected by the binding of substrate ATP-Mg^(2+). Absorption and emission spectroscopic properties of the enzyme reacted with o-phthalaldehyde strongly indicated the fomlation of isoindole derivative that crosslinks a histidine and a lysine residue. Furthermore the enzyme reacted with o-phthalaldehyde showed less number of reactive histidine residue while free thiol groups remained intact. The enzyme treated with diethypyrocarbonate completely failed to form the fluorescent adduct. Those lines of results suggest that a histidine and a lysine residue connected with catalytic activity are located very close to each other near or at the ATP binding site of the enzyme molecule.
한종원,Gwang Hoon Kim,Key Pyoung Lee,Minchul Yoon 한국조류학회I 2007 ALGAE Vol.22 No.2
The expression of genes responding to cold stress in a freshwater alga, Spirogyra varians, was studied by using differential expression gene (DEG) method. A gene strongly up-regulated in 4°C was isolated and designated as SVCR2 (Spirogyra varians cold regulated) gene. The cDNA encoding SVCR2 was cloned using λZAP cDNA library of Spirogyra varians. The deduced amino acid had a sequence similarity with trans-membrane protein in Arabidopsis thaliana (Q9M2D2, 52.7%). Northern blot analysis demonstrated that transcript level of SVCR2 increased about 10 fold under low temperature (4°C), compared with that cultured at warm (20°C) conditions. The expression of SVCR2 was also affected by light conditions. When the plants were exposed to high light (HL) (1200 μmol photon m–2 s–1), the expression of SVCR2 began within 2 hrs. This gene expression lasted for 4 hrs and decreased afterwards. Under the blue light (470 nm) condition, the expression of this gene was induced in same way as HL treatment, even under less than 100 μmol photon m–2 s–1. But red light (650 nm) and UV-A irradiation did not affect the expression of SVCR2.
한종원,Gwang Hoon Kim,Key Pyoung Lee,Minchul Yoon 한국조류학회I 2007 ALGAE Vol.22 No.2
Conventional methods for the isolation and purification of mRNA from Zygnema were unsuccessful because of its high amount of pigments and RNA interactive molecules. In particular, pigments were difficult to remove using conventional protocols because they interacted with RNA during pulverization of the materials. This resulted in total degeneration of RNA in two to three hours. To alleviate this problem, we developed an isolation method that utilized DEAE-cellulose resin. The pigments bound to DEAE anion exchange resin and separated from the RNA. Purified total RNA showed an yield of 50 μg per 100 mg of tissue with this method. The amplified 2nd strand cDNA was distributed 300 bp and over.