• 대한핵의학회지
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• 제6권1호
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• pp.17-24
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• 1972

Utilizing the commercial radioimmunoassay kit, the author assayed HGH and evaluated the problems of the method. The method had the sensitivity of 0.5 mug/ml degree and could determine the plasma HGH concentration directly without the help of plasma extraction. Also it was specific for the HGH, when tested by a dilution method using test utilizing the plasma of the acromegalic patient. The author also obtained the $^{125}I$ labelled HGH of specific activity of $156.3{\mu}Ci/{\mu}g$, performing the chloramine-T method.

• 대한핵의학회지
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• 제1권1호
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• pp.83-87
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• 1967

$^{131}I$ 및 $^{125}I$를 함유(含有)하는 Hippuran, L-Thyroxine, Triiodothyronine, Rose Bengal, RISA, MAA, Triolein, Oleic acid 및 주사용(注射用) 옥소액(沃素液_의 합성방식(合成方式)과 $^{203}Hg$을 함유(含有)하는 Neohydrine의 합성방식(合成方式)을 각각(各各) 연구(硏究)하여 표지수율(標識收率) $100{\sim}60%$의 좋은 결과(結果)를 얻었다. 합성방식(合成方式)에서는 교환법(交換法), 옥화법(沃化法)을 사용(使用)하였고 특(特)히 Chloramin-T를 이용(利用)한 저온(低溫) 옥화반응(沃化反應)을 이용(利用)하였다. 합성품(合成品)의 제제법(製劑法) 및 pyrogen free 시험결과(試驗結果)를 기술(記述)하였으며 당연구소(當硏究所)에서의 제품분배(製品分配) 상황(狀況)을 보고(報告)하였다.

• 대한화학회지
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• 제11권2호
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• pp.51-55
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• 1967

放射性 沃化反應 中 分解하기 쉬운 化合物의 沃化反應으로 有用한 低溫沃化反應에 關하여 硏究하였다. Chloroamine-T를 利用한 沃化反應은 低溫에서 높은 收率로 放射性 沃化反應을 進行시킬 수 있었으며, 活性化된 芳香核이 있는 또는 이에 類似한 아미노酸, 蛋白質化合物, 各 種 Phenol類의 沃化가 不可能하였으나 二重結合化合物 및 一般化合物엔 큰 效果가 없었다. 反應收率은 $100{\sim}60%$이었으며, 各 化合物의 試藥에 對한 反應度는 親電子反應에 對한 芳香核의 反應度와 比例하는 것이었다. 反應操作을 記述하였으며 反應過程을 考察하였다.

• 미생물학회지
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• 제35권2호
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• pp.133-138
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• 1999

Bacillus subtilis ED 213의 cytidine deaminase 의 활성부위에 존재하는 필수 아미노산잔기를 화학수식 방법으로 측정하였다. 본 효소는 1mM o-phenanthroline 에 의하여 효소활성이 43% 저해되어 효소활성 발현에 Fe\sup 2+\가 요구된다고 추정되며, 1mM ethylenediaminetetraacetic acid 에 의해서는 효소활성이 오히려 28% 정도 촉진되었다. 본 효소는 1mM N-bromosuccinimide, 1mM chloramine-T 와 1mM $\rho$-chloromercuribenzoic acid에 의하여 100% 저해되었으며, 그의 저해 양상은 경쟁적 저해 양상을 나타내었다. 본 효소의 효소활성은 1mM pyridoxal-5-phosphate 에 의항 36% 저해되었으며, 1mM 1ethyl-3-carbodiamide 와 1mM glycine methylester에 의해 저해된 효소활성이 5mM cysteine에 의해 완전히 회복되었다. 이상의 결과로부터 Bacillus subtilis ED 213 cytidine deaminase의 활성부위에는 tyrosine, methionine, cysteine 과 serine 잔기가 관여할 뿐만 아니라 lysine 과 glycine 도 효소활성에 관여하는 것으로 추정된다.

• 대한방사성의약품학회지
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• 제3권1호
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• pp.44-51
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• 2017

Herein we report an efficient radiolabeling method based on a rapid condensation reaction between N-terminal cysteine and 2-cyanobenzothiazole (CBT). Radioiodination of 2-cyano-6-hydroxybenzothiazole 2 was carried out using chloramine-T to give $^{125}I$-labeled CBT ([$^{125}I$]1) with a high radiochemical yield ($90{\pm}6%$ isolated yield, n=3) and radiochemical purity (>99%). To evaluate the radiolabeling efficiency of $^{125}I$-labeled CBT, model compounds, L-cysteine and N-terminal cysteine conjugated cRGD peptide were reacted with [$^{125}I$]1 under mild conditions. The radiolabeling reactions rapidly provided the $^{125}I$-labeled products [$^{125}I$]5 and [$^{125}I$]6 with excellent radiochemical yields and radiochemical purity. Therefore, we demonstrate that [$^{125}I$]1 will be a useful prosthetic group for radioactive iodine labeling of N-terminal cysteine bearing biomolecules.

• 대한방사성의약품학회지
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• 제3권2호
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• pp.98-102
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• 2017

We demonstrate a detail protocol for the radiosynthesis of a $^{125}I-labeled$ tetrazine prosthetic group and its application to the efficient radiolabeling of trans-cyclooctene-group conjugated human serum albumin (3) using inverse-electron-demand Diels-Alder reaction. Radioiodination of the stannylated precursor (2) was carried out by using [$^{125}I$]NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified $^{125}I-labeled$ azide ([$^{125}I$]1) was obtained with high radiochemical yield ($65{\pm}8%$, n = 5) and excellent radiochemical purity (>99%). Inverse-electron-demand Diels-Alder reaction between ([$^{125}I$]1) and 3 gave the $^{125}I-labeled$ human serum albumin ([$^{125}I$]4) with more than 99% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly indicate that the present radiolabeling method will be useful for the efficient and convenient radiolabeling of trans-cyclooctene-group containing biomolecules.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.180-185
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• 2005

Cytosine deaminase (cytosine aminohydrolase, EC 3.5.4.1) stoichiometrically catalyzes the hydrolytic deamination of cytosine and 5-fluorocytosine to uracil and 5-fluorouracil, respectively. Amino acid residues located in or near the active sites of the intracellular cytosine deaminase from chromobacterium violaceum YK 391 were identified by chemical modification studies. The enzymic activity was completely inhibited by chemical modifiers, such as 1mM NBS, chloramine-T, $\rho-CMB,\;\rho-HMB$ and iodine, and was strongly inhibited by 1mM PMSF and pyridoxal 5'-phosphate. This chemical deactivation of the enzymic activity was reversed by a high concentration of cytosine. Furthermore, the deactivation of the enzymic activity by $\rho-CMB$ was also reversed by 1mM cysteine-HCI, DTT and 2-mercaptoethanol. These results suggested that cysteine, tryptophan and methionine residues might be located in or near the active sites of the enzyme, while serine and lysine were indirectly involved in the enzymic activity. The intracellular cytosine deaminase from C violaceum YK 391 was assumed to be a thiol enzyme.

• Nuclear Engineering and Technology
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• 제12권2호
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• pp.81-87
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• 1980

락토퍼옥시데이즈(lactoperoxidase, LPO)를 사용하여 인슈린을 $^{125}$/I로 표지반응 시켰다. 반응생성물은 전분젤 전기영동(SGE) 과 세파덱스 젤여과(SF) 둥 두단계를 거쳐 정제하였다. 표지수율 과표지생성물의 항체에 대한 결합능으로 보아 종래의 클로라민-T법 (표지수율 약 35%)보다 효소법 (표지수율 약 50%)이 우수하였다. 인슈린의 첨가없이 LPO법으로 표지반응을 진행시킨 다음 SGE, 종이 크로마토그래피, 방사선사진술 등을 적용하여 LPO법에서의 부산물을 확인할 수 있었다. SGE와 SF에서의 분리 분별 부분에 관해서도 분석, 토의하였다.

• 대한핵의학회지
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• 제18권1호
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• pp.55-62
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• 1984

For an effective solid-phase labelling of protein with $^{125}I$, studies on the immobilization of lactoperoxidase(LPO) on the inner wall of polystyrene tubes were carried out. Labelling of bovine serum albumin(BSA) and insulin was also practiced using the LPO immobilized tubes. The immobilized enzyme of about $2.5{\mu}g/tube$ was sufficient for small scale labelling since the results of radio-paper chromatography of the labelling mixture of insulin indicated that the yields were sufficiently high(80%) even in the reactions conducted at room temperature for 60 sec. The results of the Sephadex column chromatography indicated that the labelled products were not contaminated with $LPO-^{125}I$, and the radiochemical purity of the products was more than 90%. In considering the general trend that the $^{125}I$ labelled protein obtained by using LPO maintains its intactness better than those obtained by using chloramine-T, together with the tendency of yield enhancing with increase of reactants-concentration, the LPO immobilized tube method is estimated to be one of the simple methods of labelling. The product might be applicable without further purification.

• Journal of Microbiology and Biotechnology
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• 제8권6호
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• pp.581-587
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• 1998

Essential amino acids involved in the catalytic role of the extracellular cytosine deaminase from Chromobacterium violaceum YK 391 were determined by chemical modification studies. The enzyme activity required the reduced form of Fe (II) ion, since the enzyme was inhibited by ο-phenanthroline. The enzyme activity was completely inhibited by the chemical modifiers, such as p-chloromercuribenzoate (p-CMB), p-hydroxymercuribenzoate, and chloramine-T at 1 mM each. The enzyme activity was also markedly inhibited by pyridoxal-5'-phosphate, diethyl pyrocarbonate, and phenylmethylsulfonyl fluroride at 1 mM each. The inactivation of the enzyme activity with p-CMB was reversed by a high concentration of cytosine. Furthermore, the inactivation of the enzyme activity with p-CMB was also reactivated by 1 mM dithiothreitol, 1 mM 2-mercaptoethanol, 1 mM cysteine-HCI, 10% ethyl alcohol, and 10% methyl alcohol. These results suggested that cysteine and methionine residues might be located in or near the active site of the enzyme, while lysine, histidine, and serine residues might be indirectly involved in the enzyme activity.