• Title/Summary/Keyword: Biophysics

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Using the New Developed Equation to Reproduce the Enthalpies of Transfer of Urea from Water to Aqueous Ethanol, Propan-1-ol and Acetonitrile at 298 K

  • Behbehani, G. Rezaei;Tazikeh, E.;Saboury, A.A.
    • Bulletin of the Korean Chemical Society
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    • v.27 no.2
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    • pp.208-210
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    • 2006
  • The enthalpies of transfer, $\Delta H_t^\theta$, of urea from water to aqueous ethanol, EtOH, propan-1-ol, PrOH, and acetonitrile, MeCN, are reported and analysed in terms of the new solvation theory. The analyses show that the solvation of urea is random in the considered solvent mixtures. It is also found that urea interact more strongly with EtOH or PrOH than water.

Recognition of substrates by membrane potential

  • Yun, Kyu-sik;Tak, Tae-moon;Kim, Jong-ho
    • Proceedings of the Membrane Society of Korea Conference
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    • 1998.04a
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    • pp.31-35
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    • 1998
  • 1. INTRODUCTION : Recognition and binding of organic substrates by biological molecules are of vital importance in biophysics and biophysical chemistry. Most studies of the application focused on the development of biosensors, which detected reaction products generated by the binding between enzymes and substrates. Other types of biosensors in which membrane proteins (e.g., nicotinic acetylcholine receptor, auxin receptor ATPase, maltose bining protein, and glutmate receptor) were utilized as a receptor function were also developed. In the previous study[1], the shifts in membrane potential, caused by the injection of substrates into a permeation cell, were measured using immobilized glucose oxidase membranes. It was suggested that the reaction product was not the origin of the potential shifts, but the changes in the charge density in the membrane due to the binding between the enzyme and the substrates generated the potential shifts. In this study, $\gamma$-globulin was immobilized (entrapped) in a poly($\gamma$-amino acid) network, and the shifts in the membrane potential caused by the injection of some amino acids were investigated.

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Genomics and Biotechnology of Plant Adaptation to the Environment

  • Mullet, John E.
    • Journal of Applied Biological Chemistry
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    • v.43 no.4
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    • pp.192-196
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    • 2000
  • The molecular basis of plant adaptation to the environment is one of the most complex areas of plant science and an understanding of this subject is critical to our ability to feed an increasing word population. Research on plant adaptation to the environment often involves two complementary approaches; top-down studies of well-adapted plants with the goal of identifying and describing the biochemical basis of adaptation and bottom-up targeted analysis of specific biochemical mechanisms with the goal of understanding how these mechanisms contribute to overall plant performance. This brief review will provide examples of both of these approaches by describing the study of sorghum's adaptation to dry environments and the role of a blue light responsive chloroplast promoter that helps protect plants against damage by high irradiance.

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NMR STRUCTURE DETERMINATION OF A NOVEL CONOTOXIN, [Pro 7,13] $\alpha$A-conotoxin $P_{IVA}$

  • Han, Kyou-Hoon;Hwang, Kae-Jung;Kim, Seung-Moak;Kim, Soo-Kyung;William R. Gray;Shon, Ki-Joon;Jean Rivier;Baldomero M. Olivera
    • Proceedings of the Korean Biophysical Society Conference
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    • 1996.07a
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    • pp.10-10
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    • 1996
  • High-resolution solution conformation of a novel conotoxin, [Pro 7,13] $\alpha$A-conotoxin $P_{IVA}$, GCCGSYPNAACHPCSCKDROSYCGQ-N $H_2$, has been determined by two-dimensional $^1$H nmr methods in combination with distance geometry calculation to rmsd values of 0.90 $\AA$ and 1.16 $\AA$ for the backbone and heavy atoms, respectively. Total of 324 NOE-derived interproton distance restraints including 33 long-range NOE restraints a well as 11 $\Phi$ and 7 $\chi$$^1$ torsion angle restraints were used for computation of structures. (omitted)d)

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Effects of n-Alkanols on the Lateral Diffusion of Total Phospholipid Fraction Extracted from Brain Membranes

  • Chung, In-Kyo;Kang, Jung-Sook;Yun, Il
    • Archives of Pharmacal Research
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    • v.16 no.3
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    • pp.191-195
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    • 1993
  • We investigated the effects of n-alkanols on the range and rate of the lateral diffusion of 1, 3-di(1-pyrenyl)propane in the model membranes of total phospholipid fraction extracted from synaptosomal plasma membrane vesicles. n-Akanols increased the range and rate of the lateral diffusion of 1, 3-di(1-pyrenyl)propane in the bulk model membrane structures (inner + outer monolayers) and the potencies of n-alknols up to 1-nonanol increased by 1 order of magnitude as the carbon chain length increases by two carbon atoms. The cut-off phenomenon was reached at 1-decanol, where further icnrease in hydrocarbon length resulted in a decrease in the lateral diffusion. However, significant changes in the 1'/1 value were not observed by methanol (from 100 to 2500 mM), ethanol (from 25 to 800 mM), and 1-propanol (from 10 to 250 mM) over entire concentration.

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DNA fingerprinting patterns of 5 serotypes of Actinobacillus actinomycetemcomitans (Actinobacillus actinomycetemcomitans의 혈청형별 제한절편장 다변화에 관한 연구)

  • Choi, Jeom-Il;Koh, Myung-Yun;Yun, Il
    • Journal of Periodontal and Implant Science
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    • v.26 no.2
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    • pp.365-375
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    • 1996
  • 5 serotypes(a, b, c, d, e) of Actinobacillus actinomycetemcomitans showed distinct hybridization patterns(DNA fingerprinting patterns) when the bacterial DNA were hybridized with randomly cloned 4.7-Kb sized DNA probe. The sizes of hybridized bands in each serotypes were different among serotypes and represented unique patterns of hybridization with the probe used. The serotype a showed two bands of fingerprinting patterns: 23.1 kb and 2.5 kb respectively. Serotype b and c showed single band: 6.6 kb and 9.5 kb, respectively. Serotype d and e showed two bands of hybridization: 23.1 kb and 2.8 kb, and 23.7 kb and 2.1 kb, respectively. The results indicate that this standard fingerpriting patterns of DNA hybridization with 4.7 kb probe can be further used for genotyping clinical isolates of Actinobacillus 8ctinomycetemcomitansand its relevance with periodontal disease activity.

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FUNDAMENTAL STUDY FOR ROLLING-OVER MOTION OF THE BODY BY FUNCTIONAL ELECTRICAL STIMULATION(FES) (기능적전기자극에 의한 체간제어의 기초적인 연구)

  • Lee, Joon-Ha;Hoshimiya, N.
    • Journal of Yeungnam Medical Science
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    • v.7 no.2
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    • pp.103-108
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    • 1990
  • A method to roll-over the paralyzed body by means of Functional Electrical Stimulation(FES) is considered. It is demonstrated that individual joint motions necessary for the rolling-over are realized by electrical stimulation. EMG measurements are also performed to analyze the cooperative activities of the muscles during rolling over motion in a case where an upper extremity was used. These results of two experiments using normal subjects verifies the fundamental feasibility of body control by FES.

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State-of-the Art Review in Nano-Biomanipulation Technologies (나노-바이오 매니퓰레이션 기술의 현황 및 전망)

  • Kim Deok-Ho;Kim Byungkyu;Park Jong-Oh;Ju Byeong-Kwon
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.4
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    • pp.353-362
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    • 2005
  • This article describes a state-of-the art review in nano-biomanipulation technologies. Nanomanipulation of biological objects enables an in-depth study of single molecules such as DNA and RNA, and of biophysical events at the molecular level like molecular motors. Controlled nanomanipulation is challenging but essential for precisely engineering biomolecules or cells and for manufacturing functional nano-biosystems. In this paper, we summarize several contact, non-contact and hybrid methods available for nanomanipulation of biological objects. Advantages currently available methods and their limitations are also compared. Finally, we discuss possible applications of nano-biomanipulation technologies to life science and molecular medicine including cell biology, genetic engineering, biophysics, and biochemistry.

A Short Review on the Application of Combining Molecular Docking and Molecular Dynamics Simulations in Field of Drug Discovery

  • Kothandan, Gugan;Ganapathy, Jagadeesan
    • Journal of Integrative Natural Science
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    • v.7 no.2
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    • pp.75-78
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    • 2014
  • Computer-aided drug design uses computational chemistry to discover, enhance, or study drugs and related biologically active molecules. It is now proved to be effective in reducing costs and speeding up drug discovery. In this short review, we discussed on the importance of combining molecular docking and molecular dynamics simulation methodologies. We also reviewed the importance of protein flexibility, refinement of docked complexes using molecular dynamics and the use of free energy calculations for the calculation of accurate binding energies has been reviewed.