High-performance liquid chromatographic enantioseparation of N-protected ?-amino acids using nonporous silica modified by a quinine carbamate as chiral stationary phase

Piette, Veronique,L�,mmerhofer, Michael,Bischoff, Klaus,Lindner, Wolfgang Wiley (John WileySons) 1997 Chirality Vol.9 No.2

(Field Report)The Bologna Process in the Field: Student (Im)Mobility in European Higher Education -The Case of Translators and Interpreters

Alain Piette 한국외국어대학교 통번역연구소 2010 통번역학연구 Vol.13 No.2

본 논문은 벨기에 몽스대학 국제통역대학원(Ecole d’Interprètes Internationaux de l’Université de Mons) 학장이 ‘볼로냐 프로세스’ 유럽고등교육 개혁 프로그램을 이행하면서 그 프로그램이 벨기에 불어사용권역과 특히 몽스대의 통역대학원에 어떤 시사점에 주었는지 실제적 경험을 소개한다. 먼저, 볼로냐 프로세스를 소개하고 현재 진행 중인 개혁 과정에 대해 간단히 기술한다. 볼로냐 프로세스의 가장 핵심적인 문제는 유럽지역 학생들이 국가 상호간 문화적 갈등, 언어적, 재정적 부담을 해결하는 것이다. 몽스 통번역대학원은 2004 년 다른 5 개 통번역대학원과 이 프로그램을 가동하여 2009 년 첫 졸업생을 배출했다. 이 프로세스는 국가간 통번역 커리큘럼의 교환과 ECTS 를 통해 학자금 문제를 해결했다. 아직도 많은 대학원이 타 국가의 통번역대학부생들의 자격동등문제를 고민하고 있지만, 이는 몽스대학원이 경험했듯이, 장기적 교육개념에 의하여 개선될 것이다. 아직도 볼로냐 프로세스는 개인이 처리해야 할 재정문제와 학업성취도를 직접 도울 수 없는 한계, 교환학생의 지역언어 및 영어사용문제 등을 지녔지만, 이 프로세스는 통번역 대학과 대학원 학생 교류에 있어서 지난 200 년간 지속해 왔던 에라스무스 장학 프로그램의 현대적 성과라 볼 수 있으며 유럽 교육의 통합적 프로그램을 제시하는 중에 있다 할 것이다.

Possible Role of Oxygen Rodicals in the Pathogenesis of Cancer , Reperfusion injury and Infectious Peritonitis

Lawrence H . Piette,Y . M . Kim 생화학분자생물학회(구 한국생화학분자생물학회) 1991 추계학술대회집 Vol.- No.-

Accelerating decarbonization with connected communities

Mary Ann Piette(메리 앤 피에트) 국토교통부, 국토교통과학기술진흥원 2022 스마트시티 탑 아젠다(Smart City Top Agenda) Vol.2 No.E

H2O2 에 의해 생성된 myoglobi 자유라디칼에 대한 ESR 연구

홍순주,Lawrence H . Piette ( Sun Joo Hong,Lawrence H . Piette ) 생화학분자생물학회 1989 BMB Reports Vol.22 No.2

Metmyoglobin when incubated with hydrogen peroxide in the presence of the spin trap, 5,5-dimethyl pyrroline-N-oxide (DMPO) has produced an asymmetric ESR spectrum, consisting of five broad lines of different intensities, in which no evidence of DMPO/OH radical adduct was detected. This result was found to be consistent to other incubation in which metmyoglobin was mixed with Fenton`s reagent in the presence of DMPO. Furthermore, DMPO/OH radical adducts validated by the characteristic ESR quartet while incubating Fenton`s reagent with DMPO, disappeared completely and was displaced by the asymmetric broad five line signal immediately after addition of metmyoglobin to this incubation solution. These results strongly suggest that not only both of the primary and secondary radical species formed in the vicinity of the heme active site and hence trapped by DMPO, but also additional DMPO/OH radical adducts formed on the surface of the protein molecule by Fenton`s reagent/DMPO incubation are together strongly immobilized in the heme pocket of the myoglobin molecule. A similar incubation in which metmyoglobin was mixed with hydrogen peroxide in the presence of the spin trap 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (TMPO), however, gave a quite different ESR spectrum with two different signal species, a sharp triplet of equal intensities with a parameter a_N 6.8 G, and a broad, structureless signal covering about 40 G. This indicates that the TMPO, having two more substituents, traps radicals formed on the surface of the protein molecule, in contrast to DMPO, due to the increased steric hindrance and hence can hardly enter into the heme pocket. The broad signal species was ascribed to the TMPO radical adduct formed with α-carbon atom in backbone and the triplet to that formed with side chains.

커넥티드 커뮤니티를 위한 탈탄소화 촉진

메리 앤 피에트(Mary Ann Piette) 국토교통부, 국토교통과학기술진흥원 2022 스마트시티 탑 아젠다(Smart City Top Agenda) Vol.2 No.1

Electron Spin Resonance Studies of spin-Trapped Free Radicals Produced by Reaction of Metmyoglobins with Hydrogen Peroxide

홍순주,Hong, Sun-Joo,Piette, Lawrence H. 생화학분자생물학회 1989 한국생화학회지 Vol.22 No.2

Metmyoglobin을 spin trap 5,5-dimethyl pyrroline-N-oxide (DMPO) 존재 아래 $H_2O_2$반응시켰을 때, 폭이 넓은 다섯 가닥의 비대칭 ESR spectrum을 얻었는데, 기대했던 DMPO/OH adduct의 흔적은 찾을 수 없었다. 또 이 metmyoglobin을 DMPO 존재 아래서 Fenton 시약과 반응시켰을 때도 동일한 결과를 얻었을 뿐 아니라, Fenton 시약과 DMPO를 반응시켜 DMPO-OH adduct 생성을 ESR로 확인한 뒤에 그 용액에 metmyoglobin을 첨가했을 때, 기존의 DMPO-OH signal은 완전히 사라지고 위에서 얻었던 비대칭 다섯가닥 spectrum으로 대치되는 것을 확인했다. 이 결과는 myoglobin 분자의 heme crevice에서 생성된 1 차 및 2 차 라디칼 adduct는 물론, 단백질 분자 표면에서 Fenton 시약에 의해 생성된 DMPO/OH까지도 heme pocket 안에 굳게 고정되는 때문인 것으로 해석했다. 한편 DMPO 대신에 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (TMPO)를 사용했더니 DMPO의 경우와는 아주 다르게, 두 종류의 라디칼로 혼성된 ESR spectrum을 얻었는데. 그 중에서 폭넓은 특정 구조가 없는 signal은 TMPO가 단백질 backbone에 있는 ${\alpha}-$ 탄소 라디칼과, 그리고 선명한 세가닥 signal은 단백질의 곁가닥 라디칼과 이룩한 adduct를 각각 나타내는 것으로 해석된다. 그런데 TMPO는 DMPO보다 메틸기를 두 개 더 가지고 있어서 보다 큰 입체적 장애를 받아 pocket에는 들어갈 수가 없고, 단백질 분자의 표면에 생성된 라디칼만을 포착하는 것으로 이해된다. Metmyoglobin when incubated with hydrogen peroxide in the presence of the spin trap, 5,5-dimethyl pyrroline-N-oxide (DMPO) has produced an asymmetric ESR spectrum, consisting of five broad lines of different intensities, in which no evidence of DMPO/OH radical adduct was detected. This result was found to be consistent to other incubation in which metmyoglobin was mixed with Fenton's reagent in the presence of DMPO. Furthermore, DMPO/OH radical adducts validated by the characteristic ESR quartet while incubating Fenton's reagent with DMPO, disappeared completely and was displaced by the asymmetric broad five line signal immediately after addition of metmyoglobin to this incubation solution. These results strongly suggest that not only both of the primary and secondary radical species formed in the vicinity of the heme active site and hence trapped by DMPO, but also additional DMPO/OH radical adducts formed on the surface of the protein molecule by Fenton's reagent/DMPO incubation are together strongly immobilized in the heme pocket of the myoglobin molecule. A similar incubation in which metmyoglobin was mixed with hydrogen peroxide in the presence of the spin trap 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (TMPO), however, gave a quite different ESR spectrum with two different signal species, a sharp triplet of equal intensities with a parameter $a_N$ 6.8 G, and a broad, structureless signal covering about 40 G. This indicates that the TMPO, having two more substituents, traps radicals formed on the surface of the protein molecule, in contrast to DMPO, due to the increased steric hindrance and hence can hardly enter into the heme pocket. The broad signal species was ascribed to the TMPO radical adduct formed with ${\alpha}$-carbon atom in backbone and the triplet to that formed with side chains.

An ESR Study of Amino Acid and Protein Free Radicals in Solution Part Ⅲ. ESR Study of Lysozyme Free Radical Produced by $Ti-H_2O_2$ Flow System

홍순주,Hong, Sun-Joo,Piette, L.H. Korean Chemical Society 1971 대한화학회지 Vol.15 No.4

Free radicals of lysozyme produced by $Ti-H_2O_2$ system were studied in aqueous solution at room temperature using ESR with a continuous flow-mixing. The spectra, each consisting of a doublet with 5.5 G splitting and a broad resonance covering 80 G splitting are closely similar in shape to that for solid irradiated in vacuum at $77^{\circ}K$ and observed at room temperature immediately on warming. The result is assumed to indicate that the secondary protein radical components formed within 0.01 second, dead time of the mixing chamber, and initiated by hydrogen atom abstraction at ${\alpha}$-carbon atom of peptide chain in liquid solution at room temperature are identical to those resulting from the initial formation of a mixture of positive holes and negative ions by ionization processes as well as radical fragments by the rupture of chemical bonds in the solid during similar time at the same temperature. A broad resonance is observed with considerable amplitude on the high field side of the doublet, which is quite dissimilar to the spectra of irradiated solid lysozyme. This resonance was tentatively attributed to the polypeptide free radical in which unpaired electrons are localized on side chain.

An ESR Study of Amino Acid and Protein Free Radicals in Solution Part VI. Enzymatic Inactivation of Lysozyme in Aqueous Solution Resulting from Exposure to $Ti-H_2O_2$ System and Gamma-Irradiation

Hong, Sun-Joo,Piette, L.H. Korean Chemical Society 1972 대한화학회지 Vol.16 No.2

The activity change of lysozyme resulted from its exposure to $Ti-H_2O_2$system in aqueous liquid at room temperature and to ${\gamma}$-irradiation in ice at $195^{\circ}K$ has been measured at room temperature with a Cary-14 spectrophotometer. The enzymatic activity of lysozyme which had been added to a previously flow-mixed solution of $TiCl_3$ and $H_2O_2$ (System I) was compared with the activity of a lysozyme-$H_2O_2$ solution after flow-mixing with $TiCl_3$ (System II), considering the differences between these two activity changes as the extent of the enzymatic inactivation by the involvement of OH radical reaction. The fraction of lysozyme inactivated by OH radical in the system containing 0.0025 M $TiCl_3-0.1M$ $H_2O_2$ (ph 3.5) was 13%, When the $TiCl_3$ concentration is double (pH 3.0), the fraction of enzyme inactivated increases to 36%. The activity of the system containing 0.025 M $TiCl_3-0.1$ M $H_2O_2$ (pH 1.5) was essentially zero. The results seem to support the previos view that the production of OH radical should be proportional to $TiCl_3$ concentration when $H_2O_2$ is present in excess. Increase in the extent of inactivation found in system I with increasing $TiCl_3$ concentration may be due to a pH effect. $H_2O_2$ seems to be less effective than $TiCl_3$ in the inactivation. 1% lysozyme solution, when ${\gamma}$-irradiated with a total dose of 3M rads, loses about 20% of its activity. Lowering of temperature also was found to yield a reduction in enzymatic activity.

용액에서의 아미노산 및 단백질 자유기에 관한 ESR 연구 제 2 보 Ti - H2O2 flow system 으로 만든 아미노산 자유기의 동정

홍순주,L . H . Piette ( Sun Joo Hong ) 생화학분자생물학회 1971 BMB Reports Vol.4 No.1

Free radicals generated by exposing amino acids to Ti-H₂O₂ flow mixing system were identified by electron spin resonance spectroscopy. Hydrogen atom abstraction by the reactive primary radical, having electrophilic character, was found to occur at the carbon atom furthest from the guanidium, carboxyl and protonated amino group, and sulfur atom. The main radical species from DL-leucine, DL-methionine and L (+) arginine were assigned to be CH₂CH (CH₃) CH₂CH (NH₃^+)COO^-, CH₃SCH₂CHCH(NH₃^+)COO^- and NH=C(NH₂)NHCH₂CHCH₂CH(NH₃^+) COO^- respectively. The splitting for the hydroxyl hydrogen was also clearly observed in the system for DL-serine free radical, CH (OH) CH (NH₃^+) COO^-. Generally, HCl appeared to interfere with the free radical production for most of the amino acids investigated except L-cysteine and DL-methionine in contrast with H₂SO, which enhances most signals but not with the latter.