• Mass Spectrometry Letters
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• v.9 no.1
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• pp.17-23
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• 2018

Studies on the interactions of amyloidogenic proteins with trace metals, such as copper, have indicated that the metal ions perform a critical function in the early oligomerization process. Herein, we investigate the effects of Cu(II) ions on the active sequence regions of amyloidogenic proteins using electrospray ionization mass spectrometry (ESI-MS) and collision induced dissociation tandem MS (CID-MS/MS). We chose three amyloidogenic peptides NNQQNY, LYQLEN, and VQIVYK from yeast prion like protein Sup35, insulin chain A, and tau protein, respectively. [Cu-peptide] complexes for all three peptides were observed in the mass spectra. The mass spectra also show that increasing Cu(II) concentrations decrease the population of existing peptide oligomers. The tandem mass spectrum of NNQQNY shows preferential binding for the N-terminal region. All three peptides are likely to appear to be in a Cu-monomer-monomer (Cu-M-M) structure instead of a monomer-Cu-monomer (M-Cu-M) structure.

• Bulletin of the Korean Chemical Society
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• v.7 no.1
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• pp.45-50
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• 1986

Separation of optical isomers of some derivatives of amino acids by reversed-phase HPLC has been accomplished by adding a chelate of an optically active amino acid to copper(Ⅱ) to the mobile phase. Cu(Ⅱ) complexes of L-proline and L-hydroxyproline in the mobile phase showed different degrees of separation. Optical isomers of DNS derivatives of amino acids are selectively separated, but those of several other derivatives are not at all. The kinds of buffer agents, the pH, and the concentrations of acetonitrile and the Cu(Ⅱ) ligand all affect the separations. The elution behavior between D and L DNS-amino acids appears to depend on the alkyl side chain of the amino acids. A chromatographic mechanism is proposed that is based on a stereospecificity of the formation of ternary complexes by the D, L-DNS-amino acids and the chiral additive associated with the stationary phase. The steric effects of the ligand exchange reactions are related with the feasibility of cis and/or trans attack of the amino acids to the binary chiral chelate retained on the stationary phase.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.152-163
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• 2005

Lipid peroxidation is a primary cause of quality deterioration in meat and meat products. Free radical chain reaction is the mechanism of lipid peroxidation and reactive oxygen species (ROS) such as hydroxyl radical and hydroperoxyl radical are the major initiators of the chain reaction. Lipid peroxyl radical and alkoxyl radical formed from the initial reactions are also capable of abstracting a hydrogen atom from lipid molecules to initiate the chain reaction and propagating the chain reaction. Much attention has been paid to the role of iron as a primary catalyst of lipid peroxidation. Especially, heme proteins such as myoglobin and hemoglobin and "free" iron have been regarded as major catalysts for initiation, and iron-oxygen complexes (ferryl and perferryl radical) are even considered as initiators of lipid peroxidation in meat and meat products. Yet, which iron type and how iron is involved in lipid peroxidation in meat are still debatable. This review is focused on the potential roles of ROS and iron as primary initiators and a major catalyst, respectively, on the development of lipid peroxidation in meat and meat products. Effects of various other factors such as meat species, muscle type, fat content, oxygen availability, cooking, storage temperature, the presence of salt that affect lipid peroxidation in meat and meat products are also discussed.

• Journal of Life Science
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• v.26 no.8
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• pp.963-969
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• 2016

Kinesin superfamily proteins (KIFs) are microtubule-dependent molecular motor proteins essential for the intracellular transport of organelles and protein complexes in cells. Kinesin 1 is a member of those KIFs that transport various cargoes, including organelles, synaptic vesicles, neurotransmitter receptors, cell signaling molecules, and mRNAs through interaction between its light chain subunit and the cargoes. Kinesin light chains (KLCs) are non-motor subunits that associate with the kinesin heavy chain (KHC) dimer. KLCs interact with many different binding proteins, but their particular binding proteins have not yet been fully identified. We used the yeast two-hybrid assay to identify proteins that interact with the tetratricopeptide repeat (TPR) domain of KLC1. We found an interaction between the TPR domain of KLC1 and Wiskott-Aldrich syndrome protein family member 1 (WAVE1), a member of the WASP/WAVE family involved in regulation of actin cytoskeleton. WAVE1 bound to the six TPR domain-containing regions of KLC1 and did not interact with KHCs (KIF5A, KIF5B, and KIF5C) in the yeast two-hybrid assay. The carboxyl (C)-terminal verprolin-cofilin-acidic (VCA) domain of WAVE1 is essential for interaction with KLC1. Also, other WAVE isoforms (WAVE2 and WAVE3) interacted with KLC1 in the yeast two-hybrid assay. When co-expressed in HEK-293T cells, WAVE1 co-localized with KLC1 and co-immunoprecipitated with KLC1 and KIF5B. These results suggest that kinesin 1 motor protein may transport WAVE complexes or WAVE-coated cargoes in cells.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2351-2357
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• 2011

Three new metal-organic copper(II) complexes, $[Cu(H_2PZTC)_2]_n{\cdot}2nH_2O$ (1), $[Cu(HPZTC){\cdot}2H_2O]_n{\cdot}2nH_2O$ (2), and $Cu_2[(PZHD)(OH)(H_2O)_2]_n$ (3) ($H_3PZTC$ = pyrazine-2,3,5-tricarboxylic acid, $PZHD^{3-}$ = 2-hydroxypyrazine-3,5-dicarboxylate), have been synthesized from $Cu(II)/H_3PZTC$ system under different synthetic conditions, and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis. In complexes 1 and 2, $H_3PZTC$ ligands loose one and two protons, which were transformed into $H_2PZTC^-$ anion and $HPZTC^{2-}$ dianion under different preparation condition, respectively. Furthermore, two ligands coordinate with Cu(II) cations in different modes, leading to the formation of the different chain structures. In complex 3, $H_3PZTC$ ligand was converted into a new ligand-PZHD by in situ decarboxylation and hydroxylation under a higher pH value than that for complexes 1 and 2. PZHD ligands link the Cu(II) cations to form a 2D layer structure. These results demonstrate that the preparation conditions, including pH value and reaction temperature etc, play an important role in the construction of complexes based on $H_3PZTC$ ligand.

• Journal of the Korean Mathematical Society
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• v.48 no.4
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• pp.749-774
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• 2011

Given a Morse function on a manifold whose moduli spaces of gradient flow lines for each action window are compact up to breaking one gets a bidirect system of chain complexes. There are different possibilities to take limits of such a bidirect system. We discuss in this note the relation between these different limits.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.926-932
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• 2008

Human heavy chain (H-) and light chain (L-) ferritins were amplified from a human cDNA library. Each ferritin gene was inserted downstream of the T7 promoter of bacterial expression vectors, and two types of coexpression vectors were constructed. The expression levels of recombinant ferritins ranged about 26-36% of whole-cell protein. H-ferritin exhibited a lower expression ratio compared with L-ferritin, by a coexpression system. However, the coexpression of HL-ferritins was significantly increased above the expression ratio of H-ferritin by cultivation without IPTG induction overnight. Purified recombinant H-, L-, HL-, and LH-ferritins were shown to be homo- and heteropolymeric high molecular complexes and it was indicated that their assembled subunits would be able to work functionally in the cell. Thus, these results indicate an improvement in the expression strategy of H-ferritin for heteropolymeric production and studies of ferritin assembly in Escherichia coli.

• Bulletin of the Korean Chemical Society
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• v.11 no.3
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• pp.238-240
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• 1990

$^{31}P${$^1H$} nuclear Overhauser effects (NOEs) have been obtained for complexes formed between apolipoprotein B (apo B) and dipalmytoylphosphatidylcholine (DPPC) vesicles. NOE measurements have been conducted with broad-band irradiation of the entire $^1H$ spectrum in order to identify the proton source of the NOE. In a unilamellar vesicle formed spontaneously upon mixing aqueous suspensions of long-chain phospholipid with small amount of short-chain lecithin, the maximum NOE occurs at the N-methyl proton resonance position of the choline moiety. With addition of cholesterol to vesicles, the position of the NOE maximum shifts further away from the choline methyl frequency. For the ternary apo B-vesicle-cholesterol complex, the position of the maximum NOE lies halfway between those in vesicles with and without cholesterol.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.31-35
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• 1996

This paper presents a real time algorithm for monitoring of the arrythmia of ECG signal. A real time monitoring, following by detecting a QRS complex, is the most important. Using 2-dimensional time-delay coordinates which are reconstructed by the phase portrait plotting special trajectory, we detect QRS complexes. In this study, arrythmias are detected by matching the past standard template with tile present pattern when changing abruptly In order to matching with each other, we propose modified chain coding algorithm which applies vetor table consisting of eight orthonormal code(=binary code) to the phase portraits. This algorithm using logical function increases the weight if exceeding to the threshold determinded by correlation value and the distance from a straight line(y=x). Evaluating the performance of the proposed algorithm, we use standard MIT/BIH database. The results are fellowing, 1) Improve the speed of matching template than that of cross-correlation ever has been used. 2) Because the proposed algorithm is robust to varing fiducial point, it is possible to monitor the ECG signal with irregular RR interval. 3) In spite of baseline wandering owing to the low frequency noise, monitoring performance is not reduced.

• Polymer(Korea)
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• v.24 no.2
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• pp.228-236
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• 2000

The preparation of organophilic clay from Na$^{+}$-MMT was achieved by intercalation of alkylammonium bromide. The dispersed organophilic clay in NMP was then added to the solution of polyamic acids (BPDA-PPD, BTDA-ODA/ MPD) in NMP. After curing at 30$0^{\circ}C$, thin films of the polyimide/clay nanocomposite were prepared. The results of X-ray diffraction (XRD) shelved that the d-spacings of dried polyamic acid (PAA)-clay complexes increased in proportion to the chain length of the onium ion and patterns of two kinds of PAA-clay complexes were similar. The d-spacings of approximately 13.2 $\AA$ for the polyimide/clay nanocomposites were independent of the initial onium ion chain length and the species of PAA. From the study of XRD and transmission electron microscopy (TEM), we found layered silicates were dispersed in polyimide matrix and the resultants were intercalated nanocomposites. TGA result showed thermal stability of polyimide nanocomposite improved a little more than the pure polyimide. From the result of dynamic mechanical property, we found that the storage modulus of the nanocomposites had increased by 1.2-1.8 times of the pure polyimides.s.