scholarly journals Salicylate Biosynthesis: Overexpression, Purification, and Characterization of Irp9, a Bifunctional Salicylate Synthase from Yersinia enterocolitica

2005 ◽  
Vol 187 (15) ◽  
pp. 5061-5066 ◽  
Author(s):  
Olivier Kerbarh ◽  
Alessio Ciulli ◽  
Nigel I. Howard ◽  
Chris Abell
Keyword(s):  
Yersinia Enterocolitica ◽  
Enzyme Assays ◽  
Purification And Characterization ◽  
Reverse Phase ◽  
H Nmr ◽  
Spectroscopic Analyses ◽  
Single Protein ◽  
Salicylate Synthase ◽  
First Time

ABSTRACT In some bacteria, salicylate is synthesized using the enzymes isochorismate synthase and isochorismate pyruvate lyase. In contrast, gene inactivation and complementation experiments with Yersinia enterocolitica suggest the synthesis of salicylate in the biosynthesis of the siderophore yersiniabactin involves a single protein, Irp9, which converts chorismate directly into salicylate. In the present study, Irp9 was for the first time heterologously expressed in Escherichia coli as a hexahistidine fusion protein, purified to near homogeneity, and characterized biochemically. The recombinant protein was found to be a dimer, each subunit of which has a molecular mass of 50 kDa. Enzyme assays, reverse-phase high-pressure liquid chromatography and 1H nuclear magnetic resonance (NMR) spectroscopic analyses confirmed that Irp9 is a salicylate synthase and converts chorismate to salicylate with a Km for chorismate of 4.2 μM and a k cat of 8 min−1. The reaction was shown to proceed through the intermediate isochorismate, which was detected directly using 1H NMR spectroscopy.

Synthesis and characterization of meso-to-meso directly linked porphyrin-diazaporphyrin triads

2018 ◽  
Vol 22 (09n10) ◽  
pp. 814-820
Author(s):  
Yingying Jia ◽  
Ling Xu ◽  
Bangshao Yin ◽  
Mingbo Zhou ◽  
Jianxin Song
Keyword(s):  
Nickel Complex ◽  
High Resolution Mass Spectrometry ◽  
Dihedral Angles ◽  
X Ray Diffraction ◽  
Extinction Coefficients ◽  
X Ray ◽  
H Nmr ◽  
First Time ◽  
Molar Extinction Coefficients

Beginning with 5,10,15-triarylporphyrin-nickel complex, five meso-to-meso directly linked porphyrin-diazaporphyrin triads were successfully prepared for the first time through a series of reactions including formylation via Vilsmeier–Haack reaction, condensation with pyrrole, bromination with [Formula: see text]-Bromosuccinimide (NBS), oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), metal-templated cyclization of dibromodipyrrin-metal complexes with NaN[Formula: see text] and demetalization. All these triads were comprehensively characterized by [Formula: see text]H NMR, high-resolution mass spectrometry and UV-vis absorption. In addition, the structure of compound 6Ni was unambiguously determined by X-ray diffraction analysis, which showed that the two dihedral angles are both 86.65 (4)[Formula: see text] between each mean plane of porphyrin and that of central diazaporphyrin The UV-vis absorption spectra disclosed that the longest wavelengths of Soret bands and Q bands for these triads were observed at 429 and 642 nm, respectively. In contrast to diazaporphyrin-porphyrin dyads, diazaporphyrin dimers and diazaporphyrin monomers reported previously the molar extinction coefficients, particularly for triad 8Ni are much higher.

Purification and characterization of ferro- and cobalto-chelatases

1988 ◽  
Vol 66 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Eduardo T. Cánepa ◽  
Elena B.C. Llambías
Keyword(s):  
Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Purification And Characterization ◽  
Degree Of Unsaturation ◽  
Apparent Homogeneity ◽  
Optimum Ph ◽  
Single Protein ◽  
Metal Insertion

Pig liver ferrochelatase was purified 465-fold with about 30% yield, to apparent homogeneity, by a procedure involving solubilization from mitochondria, ammonium sulfate fractionation, and Sephacryl S-300 chromatography. The fraction of each purification step had cobaltochelatase as well as ferrochelatase activity. A purified protein of molecular weight 40 000 was found by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. A molecular weight of approximately 240 000 was obtained by Sephacryl S-300 chromatography. Both activities of the purified fraction increased linearly with time until 2 h. but nonlinear plots were obtained with increasing concentrations of protein. Their optimum pH values were similar. Km values were, for ferrochelatase activity, 23.3 μM for the metal and 30.3 μM for mesoporphyrin. and for cobaltochelatase activity. 27 and 45.5 μM, respectively. Fe2+ and Co2+ each protected against inactivation by heat. Pb2+, Zn2+, Cu2+, or Hg2+ inhibited both activities, while Mn2+ slightly activated; Mg2+ had no effect, at the concentrations tested. There appeared to be an involvement of sulfhydryl groups in metal insertion. Lipids, in correlation with their degree of unsaturation, activated both purified activities; phospholipids also had activation effects. We conclude that a single protein catalyzes the insertion of Fe2+ or Co2+ into mesoporphyrin.

scholarly journals Structural and In Silico Characterization of Small Molecules Isolated from Eichhornia crassipes

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Andrew Mtewa ◽  
Duncan C. Sesaazi ◽  
Fanuel Lampiao
Keyword(s):  
In Silico ◽  
Eichhornia Crassipes ◽  
Cytochrome P450 Enzymes ◽  
Anticancer Activities ◽  
H Nmr ◽  
Cytotoxic Compounds ◽  
In Silico Characterization ◽  
First Time ◽  
Nonanedioic Acid

Eichhornia crassipes has been reported to have various medicinal properties including anticancer activities. The plant was collected from the Shire river in Malawi, and two cytotoxic compounds, benzene-1,4-diol and nonanedioic acid, were isolated and characterized for the first time in the leaves and roots of the plant. 1H NMR, COSY, HSQC, HMBC, 13-C, and LCMS spectroscopic experimental techniques were used to identify the compounds in their pure forms. In silico experiments showed that both compounds do not have AMES toxicity and do not inhibit cytochrome P450 enzymes, but nonanedioic acid acts as a CYP2D6 substrate. This work showed that Eichhornia crassipes can be considered to have a role as a source of potential hits and leads to drug development that can be rationally optimized for drugs.

Crystallographic and spectroscopic characterization of a mixed actinide–lanthanide carbide cluster stabilized inside an Ih(7)-C80 fullerene cage

2020 ◽  
Vol 56 (27) ◽  
pp. 3867-3870 ◽  
Author(s):  
Xiaomeng Li ◽  
Yang-Rong Yao ◽  
Wei Yang ◽  
Jiaxin Zhuang ◽  
Luis Echegoyen ◽  
...  
Keyword(s):  
Spectroscopic Characterization ◽  
Fullerene Cage ◽  
Spectroscopic Analyses ◽  
Carbide Cluster ◽  
First Time

For the first time, crystallographic and spectroscopic analyses identified that a mixed actinide–lanthanide carbide cluster Sc2UC, with a very short UC bond, is stabilized inside an Ih(7)-C80 cage.

scholarly journals Purification and characterization of human neuropeptide Y from adrenal-medullary phaeochromocytoma tissue

1984 ◽  
Vol 219 (3) ◽  
pp. 699-706 ◽  
Author(s):  
R Corder ◽  
P C Emson ◽  
P J Lowry
Keyword(s):  
Amino Acid ◽  
Neuropeptide Y ◽  
Amino Acid Analysis ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Carboxypeptidase Y ◽  
Purification And Characterization ◽  
Reverse Phase ◽  
Tryptic Fragment

Human neuropeptide Y was isolated from acid extracts of adrenal-medullary phaeochromocytoma tissue. After (NH4)2SO4 fractionation, the neuropeptide Y-like immunoreactivity was purified from the resolubilized 80%-saturation-(NH4)2SO4 peptide-rich precipitate, by gel filtration, cation-exchange chromatography and reverse-phase high-pressure liquid chromatography. Amino acid analysis of the peptide revealed a composition almost identical with that of the pig peptide, the exception being the loss of one leucine residue and its replacement with methionine. Tryptic digestion of the peptide and subsequent amino acid analysis of the fragments further confirmed the identity of the peptide. Carboxypeptidase Y digestion of the (1-19)-peptide tryptic fragment has shown the methionine to be located at position 17 in human neuropeptide Y.

scholarly journals Purification and Characterization of the Bacterial UDP-GlcNAc:Undecaprenyl-Phosphate GlcNAc-1-Phosphate Transferase WecA

2008 ◽  
Vol 190 (21) ◽  
pp. 7141-7146 ◽  
Author(s):  
Bayan Al-Dabbagh ◽  
Dominique Mengin-Lecreulx ◽  
Ahmed Bouhss
Keyword(s):  
Cell Envelope ◽  
Functional Characterization ◽  
Integral Membrane Protein ◽  
Minimal Length ◽  
Purification And Characterization ◽  
Effects Of Ph ◽  
Undecaprenyl Phosphate ◽  
First Time ◽  
Lipid Substrate

ABSTRACT To date, the structural and functional characterization of proteins belonging to the polyprenyl-phosphate N-acetylhexosamine-1-phosphate transferase superfamily has been relentlessly held back by problems encountered with their overexpression and purification. In the present work and for the first time, the integral membrane protein WecA that catalyzes the transfer of the GlcNAc-1-phosphate moiety from UDP-GlcNAc onto the carrier lipid undecaprenyl phosphate, yielding undecaprenyl-pyrophosphoryl-GlcNAc, the lipid intermediate involved in the synthesis of various bacterial cell envelope components, was overproduced and purified to near homogeneity in milligram quantities. An enzymatic assay was developed, and the kinetic parameters of WecA as well as the effects of pH, salts, cations, detergents, and temperature on the enzyme activity were determined. A minimal length of 35 carbons was required for the lipid substrate, and tunicamycin was shown to inhibit the enzyme at submicromolar concentrations.

scholarly journals Phytochemicals Screening and Chromatographic Separation of Bio Active Compound from the Roots of Berberis Lyceum

2019 ◽  
pp. 1-5
Author(s):  
Shakir Ullah ◽  
◽  
Inam Ullah ◽  
Robeena Naz ◽  
◽  
...  
Keyword(s):  
Chromatographic Separation ◽  
Research Work ◽  
Ethanol Extract ◽  
Spectroscopic Methods ◽  
H Nmr ◽  
Phytochemical Investigation ◽  
Isolated Compound ◽  
First Time ◽  
Berberis Lycium

In the present research work the phytochemical and Chromatographic separation of bio active compounds Berberis lycium occurred. Phytochemical investigation of the CH2 Cl2 /CH3 OH (1:1) extract ethanol of root shown the presence of terpenoids, flavonoids, saponins, anthraquinones and alkaloids, steroids and tannins was absent. Chromatographic separation of CH2 Cl2 /CH3 OH (1:1) root ethanol extract yielded methyl 9, 10-dihydro-3, 8-hydroxy-6-methyl-9, 10-dioxoanthracene-2- carboxylate, isolated for the first time from the species of Berberis lycium. With the help of spectroscopic methods (IR, 1 H NMR, 13C NMR, and DEPT-135 and UV-Vis,) Partial characterization of the isolated compound was done.

scholarly journals Characterization of Carotenoid and Carotenoid Esters of Astringent Persimmon Tissues (Diospyros kaki Thunb. var. Rojo Brillante). Effects of Thermal and High Pressure Non-Thermal Processing

2018 ◽  
Author(s):  
M. Pilar Cano ◽  
Andrea Gómez-Maqueo ◽  
Jorge Welti-Chanes ◽  
Tomás García-Cayuela
Keyword(s):  
High Pressure ◽  
Human Health ◽  
Thermal Processing ◽  
High Pressures ◽  
Beta Carotene ◽  
Diospyros Kaki ◽  
Reverse Phase ◽  
C30 Column ◽  
First Time

Carotenoid and carotenoid esters profiles of peel, pulp and whole fruit tissues of astringent persimmon (Diospyrus kaki Thunb., var. Rojo Brillante) have been characterized in detail and quantified for the first time. Carotenoids were determined by HPLC-PDA-MS/MS (APCI+), using a reverse phase C30 column. A total of 38 carotenoids were identified and quantified, corresponding to 21 free carotenoids (13 xanthophylls and 8 hydrocarbon carotenes) and a total of 17 carotenoid esters. The qualitative profiles are very similar among tissues, differing only in the carotenoids concentration. The most important identified free xanthophylls were (all-E)-β-cryptoxanthin, (all-E)-antheraxanthin, (all-E)-lutein, (all-E)-zeaxanthin and (all-E)-violaxanthin . Hydrocarbon carotenoids found were (all-E)-β-carotene, (all-E)-α-carotene, (9Z)-β-carotene, (13Z)-β-carotene, (9Z)-α-carotene, and lycopene. The most abundant carotenoid esters were (all-E)-lutein-3-O-palmitate, (all-E)-zeaxanthin myristate, (all-E)-zeaxanthin palmitate and (all-E)-cryptoxanthin laurate. Processing by high pressures produced no regular effect on persimmon carotenoids and pasteurization affected negatively the content of all carotenoids from all studied persimmon tissues. This work will contribute to the development of scientific research about the bioaccessibity and bioavailabity of each individual free or esterified persimmon carotenoids in order to a better understanding of the carotenoid compounds impact in human health.

Purification and characterization of fructans with β‐2, 1‐ and β‐2, 6‐glycosidic linkages suitable for enzyme studies

2020 ◽  
Author(s):  
GD BONNETT ◽  
Ian Sims ◽  
JA ST. JOHN ◽  
RJ SIMPSON
Keyword(s):  
Molecular Mass ◽  
Small Proportion ◽  
Gel Filtration ◽  
Triticum Aestivum L ◽  
High Molecular Mass ◽  
Enzyme Assays ◽  
Purification And Characterization ◽  
Linear Molecules ◽  
Low Levels

Fructan pentasaccharides were purified, in quantities suitable for use as substrates for enzyme assays, from Neosugar‐p‐(Meijj Seika Kaisha Ltd. Japan), tubers of Helianthus tuberosus L., L., and stems and leaf sheaths of Triticum aestivum L by a combination of gel‐filtration and RP‐HPLC. Fructan of higher molecular mass (mean DP = 30) was purified from Leaves of Lolium rigidum Gaud, that had been induced to accumulate fructan and characterized along; with the commercially available fructan from Cichorium intybus L. (Sigma, St Louis, USA) (mean DP = 33). The fructan pentasaccharide purified from H. tuberosus was found to contain exclusively 2, 1‐linked fructose and terminal fructose and terminal glucose, and was identified as (1, 1, 1)‐kestopentatise. The fructan pentasaccharide purified from Neosugar‐P also contained (1,1,1)‐kestopentaose. although the presence of fructan Klinked glucose and 1 % 2, 6‐linked fructose indicated that a small proportion of other kestopentaoses were present, The fructan pentasaccharide purified from T aestivum consisted of almost exclusively 2,6‐linked fructose and terminal glucose and terminal fructose and was considered to contain predominantly (6,6,6)‐kestopentaose. The presence of 1 % 2,1,6)‐linked fructose indicated the sample also contained a small proportion of branched kestopentanse. The high molecular mass fructan from C. intybus was found to comprise linear molecules containing only 2,1‐linked fructose, terminal glucose and terminal fructose‐ High molecular mass fructan from L. rigidum contained predominantly 2. h‐linked fructose, had predominantly internal glucose, indicated by 2 %, 1.6‐linked glucose, low levels of branching, indicated 2 % 2,1,6‐linked fructose residues; and 1% of the residues were 2,1 ‐linked fructose. Copyright © 1994, Wiley Blackwell. All rights reserved

Photophysical and photochemical properties of fluoroether-substituted zinc(II) and titanium(IV) phthalocyanines

2018 ◽  
Vol 22 (01n03) ◽  
pp. 46-55 ◽  
Author(s):  
İlke Gürol ◽  
Gülay Gümüş ◽  
Deniz Kutlu Tarakci ◽  
Ömer Güngör ◽  
Mahmut Durmuş ◽  
...  
Keyword(s):  
Quantum Yields ◽  
Central Metal Atom ◽  
Spectroscopic Techniques ◽  
Central Metal ◽  
Oxygen Generation ◽  
Fluorescence Quantum Yields ◽  
H Nmr ◽  
Photochemical Properties ◽  
First Time

The synthesis and characterization of novel zinc(II) (1a–4a) and oxo-titanium(IV) (1b–4b) phthalocyanine derivatives bearing 1H,1H-nona?uoro-3,6-dioxaheptan-1-ol groups are described for the first time. These phthalocyanines (1a–4a and 1b–4b) were characterized by elemental analysis and different spectroscopic techniques such as UV-vis, [Formula: see text]H NMR, FTIR and mass. Furthermore, the photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation) properties of these phthalocyanines were investigated in tetrahydrofuran (THF) solution. The influence of the number of the substituted groups (tetra or octa), position of the substituents (peripheral or non-peripheral) and central metal atom (zinc or titanium) on the photophysical and photochemical properties of these phthalocyanines were evaluated.

Sign in / Sign up

Export Citation Format

Share Document