Impact of Photon Absorption on the Electronic Properties ofp-Coumaric Acid Derivatives of the Photoactive Yellow Protein Chromophore

2004 ◽  
Vol 108 (16) ◽  
pp. 5138-5148 ◽  
Author(s):  
Lavanya L. Premvardhan ◽  
Francesco Buda ◽  
Michael A. van der Horst ◽  
Daniel C. Lührs ◽  
Klaas J. Hellingwerf ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Photon Absorption ◽  
Photoactive Yellow Protein ◽  
Coumaric Acid ◽  
Derivatives Of

scholarly journals Identification of the Tyrosine- and Phenylalanine-Derived Soluble Metabolomes of Sorghum

2021 ◽  
Vol 12 ◽  
Author(s):  
Jeffrey P. Simpson ◽  
Jacob Olson ◽  
Brian Dilkes ◽  
Clint Chapple
Keyword(s):  
Amino Acids ◽  
Cinnamic Acid ◽  
Aromatic Amino Acids ◽  
Flavonoid Glycosides ◽  
Coumaric Acid ◽  
Biotic And Abiotic Stress ◽  
Proportional Contribution ◽  
Negative Ionization ◽  
Derivatives Of

The synthesis of small organic molecules, known as specialized or secondary metabolites, is one mechanism by which plants resist and tolerate biotic and abiotic stress. Many specialized metabolites are derived from the aromatic amino acids phenylalanine (Phe) and tyrosine (Tyr). In addition, the improved characterization of compounds derived from these amino acids could inform strategies for developing crops with greater resilience and improved traits for the biorefinery. Sorghum and other grasses possess phenylalanine ammonia-lyase (PAL) enzymes that generate cinnamic acid from Phe and bifunctional phenylalanine/tyrosine ammonia-lyase (PTAL) enzymes that generate cinnamic acid and p-coumaric acid from Phe and Tyr, respectively. Cinnamic acid can, in turn, be converted into p-coumaric acid by cinnamate 4-hydroxylase. Thus, Phe and Tyr are both precursors of common downstream products. Not all derivatives of Phe and Tyr are shared, however, and each can act as a precursor for unique metabolites. In this study, 13C isotopic-labeled precursors and the recently developed Precursor of Origin Determination in Untargeted Metabolomics (PODIUM) mass spectrometry (MS) analytical pipeline were used to identify over 600 MS features derived from Phe and Tyr in sorghum. These features comprised 20% of the MS signal collected by reverse-phase chromatography and detected through negative-ionization. Ninety percent of the labeled mass features were derived from both Phe and Tyr, although the proportional contribution of each precursor varied. In addition, the relative incorporation of Phe and Tyr varied between metabolites and tissues, suggesting the existence of multiple pools of p-coumaric acid that are fed by the two amino acids. Furthermore, Phe incorporation was greater for many known hydroxycinnamate esters and flavonoid glycosides. In contrast, mass features derived exclusively from Tyr were the most abundant in every tissue. The Phe- and Tyr-derived metabolite library was also utilized to retrospectively annotate soluble MS features in two brown midrib mutants (bmr6 and bmr12) identifying several MS features that change significantly in each mutant.

scholarly journals QUANTUM CONDUCTANCE AND ELECTRONIC PROPERTIES OF LOWER DIAMONDOID MOLECULES AND DERIVATIVES

2008 ◽  
Vol 07 (01) ◽  
pp. 63-72 ◽  
Author(s):  
YONG XUE ◽  
G. ALI MANSOORI
Keyword(s):  
Electronic Properties ◽  
Single Molecule ◽  
Building Blocks ◽  
Sodium Ion ◽  
Hydrogen Ion ◽  
Ab Initio Method ◽  
Quantum Conductance ◽  
Molecular Building Blocks ◽  
Probe System ◽  
Derivatives Of

Diamondoids and their derivatives have found major applications as templates and as molecular building blocks in nanotechnology. An ab initio method we calculated the quantum conductance and the essential electronic properties of two lower diamondoids (adamantane and diamantane) and three of their important derivatives (amantadine, memantine and rimantadine). We also studies two artificial molecules that are built by substituting one hydrogen ion with one sodium ion in both adamantane and diamantane molecules. Most of our results are based on an infinite Au two-probe system constructed by ATK and VNL software, which comprise TRANSTA-C package. By changing various system structures and molecule orientations in linear Au and 2 × 2 Au probe systems, we found that although the conductance of adamantane and diamantane are very small, the derivatives of the lower diamondoids have considerable conductance at specific orientations and also showed interesting electronic properties. The quantum conductance of such molecules will change significantly by changing the orientations of the molecules, which approves that residues like nitrogen and sodium atoms have great effects on the conductance and electronic properties of single molecule. There are obvious peaks near Fermi energy in the transmission spectrums of artificial molecules, indicating the plateaus in I–V characteristics of such molecules.

Hydroxycinnamoyl: Coenzyme A Transferase Involved in the Biosynthesis of Kaempferol-3-(p-coumaroyl Triglucoside) in Pisum sativum

1977 ◽  
Vol 32 (9-10) ◽  
pp. 765-768 ◽  
Author(s):  
Marie H. Saylor ◽  
Richard L. Mansell
Keyword(s):  
Coenzyme A ◽  
Chemical Properties ◽  
Acyl Donor ◽  
Coumaric Acid ◽  
Enzyme Preparations ◽  
Naturally Occurring ◽  
Enzymatic Formation ◽  
Derivatives Of ◽  
Acid Esters ◽  
And Chemical Properties

Abstract The major flavonoids of Pisum are derivatives of kaempferol and quercetin, including both tri-glucosides and acylated triglucosides in which the acyl group is p-coumaric acid. Although hydroxy-cinnamic acid esters of flavonoids are common pigments in many plants, neither the enzymes nor the precursors involved in their biosynthesis have been demonstrated. We report here that crude enzyme preparations extracted from peas catalyze the transfer of the p-coumaroyl moiety of p-coumaroyl: Coenzyme A to kaempferol-3-triglucoside forming kaempferol-3-(p-coumaroyl triglucoside) as the acylated product. The reaction product has been vigorously shown to be identical to the naturally occurring kaempferol-3-(p-coumaroyl triglucoside) in both chromatographic and chemical properties. The enzymatic formation of the acylated derivative occurred only minimally when incubated with the cofactors required for carboxyl group activation (ligase) and maximally when incubated with p-coumaroyl : Coenzyme A as the acyl donor.

Two derivatives of phenylpyridyl-fused boroles with contrasting electronic properties: decreasing and enhancing the electron accepting ability

2021 ◽  
Vol 50 (1) ◽  
pp. 355-361
Author(s):  
Jiang He ◽  
Florian Rauch ◽  
Ivo Krummenacher ◽  
Holger Braunschweig ◽  
Maik Finze ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Derivatives Of

The pyridyl groups of two phenylpyridyl-fused boroles were transformed into an electron-rich dihydropyridine moiety or an even more electron-deficient N-methylpyridinium cation, leading to contrasting electronic properties.

FLUORESCENT METABOLITES IN VIRUS- OR RUST-INFECTED BEAN LEAVES

1965 ◽  
Vol 43 (2) ◽  
pp. 201-215 ◽  
Author(s):  
C. C. Gill
Keyword(s):  
Caffeic Acid ◽  
Paper Chromatography ◽  
Coumaric Acid ◽  
Virus Infections ◽  
New Materials ◽  
Lesion Formation ◽  
Fluorescent Materials ◽  
Derivatives Of ◽  
Fluorescent Compounds ◽  
Bean Leaves

The fluorescent substances in un-infected and virus- or rust-infected primary bean leaves were examined by paper chromatography 11 to 20 days after seeding.A relatively constant total of 17 fluorescent materials was recorded in normal leaves. For local, necrotic virus infections, totals of 20 additional fluorescent materials were recorded between [Formula: see text] and 7 days after inoculation for tobacco necrosis (TNV) and 15 between [Formula: see text] and 9 days for tobacco mosaic (TMV). Thirteen of the new materials in TMV infections appeared to be the same as some of those from TNV infections, but were quantitatively greater for the more extensively necrotic TNV lesions. One of the most prominent metabolites associated with the hypersensitive virus infections was occasionally present in trace amounts following mild leaf abrasion.Only eight materials additional to those in healthy leaves were detected in extracts from non-necrotic rusted tissue between 1 and 6 days after inoculation. Five of these were tentatively identified as common to both TNV and TMV infections and a sixth as common to TNV infections. No abnormal fluorescent materials were recorded from inoculated leaves bearing symptomless 3-day-old infections of bean strain of TMV and only a trace of one 8 days after inoculation. A rough correlation was apparent between the degree of necrosis and formation of new fluorescent compounds.Abnormal fluorescent materials were also detected in cowpea leaves bearing local lesion infections of TNV. Many of these were different from those of TNV-infected bean. The appearance of abnormal fluorescent compounds coincided with incipient virus lesion formation on bean and cowpea.Six fluorescent materials in healthy bean were tentatively identified as derivatives of caffeic acid, p-coumaric acid, or quercetin. Six major abnormal fluorescent metabolites in bean showed evidence of phenolic nature.

scholarly journals Synthesis of Novel Derivatives of Carbazole-Thiophene, Their Electronic Properties, and Computational Studies

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
E. F. Damit ◽  
N. Nordin ◽  
A. Ariffin ◽  
K. Sulaiman
Keyword(s):  
Electronic Properties ◽  
Theoretical Calculations ◽  
Energy Levels ◽  
Phenyl Group ◽  
Cyclic Voltammogram ◽  
Coupling Reactions ◽  
Lumo Energy ◽  
Homo And Lumo ◽  
Derivatives Of ◽  
Homo And Lumo Energy

A series of carbazole-thiophene dimers,P1–P9, were synthesized using Suzuki-Miyaura and Ullmann coupling reactions. InP1–P9, carbazole-thiophenes were linked at the N-9 position for different core groups via biphenyl, dimethylbiphenyl, and phenyl. Electronic properties were evaluated by UV-Vis, cyclic voltammogram, and theoretical calculations. Particularly, the effects of conjugation connectivity on photophysical and electrochemical properties, as well as the correlation between carbazole-thiophene and the core, were studied. Carbazole connecting with thiophenes at the 3,6-positions and the phenyl group as a core group leads to increased stabilization of HOMO and LUMO energy levels where the bandgap (ΔE) is significantly reduced.

scholarly journals Energetic and Geometric Characteristics of Substituents, Part 3: The Case of NO2 and NH2 Groups in Their Mono-Substituted Derivatives of Six-Membered Heterocycles

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 145
Author(s):  
Paweł A. Wieczorkiewicz ◽  
Halina Szatylowicz ◽  
Tadeusz M. Krygowski
Keyword(s):  
Active Region ◽  
Electronic Properties ◽  
Electron Density ◽  
Relative Stability ◽  
Theoretical Study ◽  
Functional Materials ◽  
Electronic Interactions ◽  
Geometric Descriptors ◽  
Energy Of Interaction ◽  
Derivatives Of

Substituted heterocyclic arenes play important roles in biochemistry, catalysis, and in the design of functional materials. Exemplary six-membered heteroaromatic molecules, that differ from benzene by inclusion of one heteroatom, are pyridine, phosphorine, arsabenzene, and borabenzene. This theoretical study concerns the influence of the heteroatom present in these molecules on the properties of substituents of two types: electron-donating (ED) NH2 group and electron-accepting (EA) NO2 group, attached at the 2-, 3-, or 4-position. The effect is evaluated by the energy of interaction (Erel) between the substituent and the substituted system and electronic properties of the substituents described by the charge of the substituent active region (cSAR) index. In addition, several geometric descriptors of the substituent and heteroaromatic ring, as well as changes in the aromaticity, are considered. The latter are assessed using the Electron Density of Delocalized Bonds (EDDBs) property of delocalized π electrons. The obtained results show that the electronegativity (EN) of the heteroatom has a profound effect on the EA/ED properties of the substituents. This effect is also reflected in the geometry of studied molecules. The Erel parameter indicates that the relative stability of the molecules is highly related to the electronic interactions between the substituent and the heteroarene. This especially applies to the enhancement or weakening of π-resonance due to the EN of the heteroatom. Additionally, in the 2-heteroarene derivatives, specific through-space ortho interactions contribute to the heteroatom effects.

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