Catalytic efficiency of divalent metal salts in dinucleoside 5',5'-triphosphate bond formation

2002 ◽  
Author(s):  
Janusz Stępiński ◽  
Jacek Jemielity ◽  
Magdalena Lewdorowicz ◽  
Marzena Jankowska-Anyszka ◽  
Edward Darżynkiewicz
Keyword(s):  
Bond Formation ◽  
Catalytic Efficiency ◽  
Divalent Metal ◽  
Metal Salts

scholarly journals Biosynthesis, purification, characterization and immobilization of laccase from Lithothelium sp.

Chemija ◽  
2020 ◽  
Vol 31 (3) ◽  
Author(s):  
Ingrida Radveikienė ◽  
Ingrida Pilotaitė ◽  
Rimgailė Dainytė ◽  
Regina Vidžiūnaitė
Keyword(s):  
Residual Activity ◽  
Catalytic Efficiency ◽  
Hydrophobic Interaction Chromatography ◽  
Metal Salts ◽  
Biotechnological Applications ◽  
Affinity Constants ◽  
Sds Page ◽  
Wide Range ◽  
Optimum Ph ◽  
Sulphate Salts

Novel fungal laccase isoenzymes (namely L95-1 and L95-2) produced by the Ascomycete Lithothelium sp. isolated from the forest soil were purified. However, only one of them was characterized, because the other isoenzyme lost its activity during purification. Extracellular L95-1 laccase was purified 30-fold using ion-exchange and hydrophobic interaction chromatography, with an overall yield of 88%. The molecular mass of purified L95-1 was estimated to be 85 kDa by SDS-PAGE analysis. L95-1 laccase was stable at temperature 4–22°C and pH 6.0–6.5. The substrate specificity of L95-1 laccase was examined with various compounds. Determined affinity constants (KM) varied in a wide range of 3.7–2020.0 µM, whereas catalytic efficiency constants (kcat/KM) covered a range of 0.008–1.9 µM–1 s–1. The optimum pH for most substrates varied in a range from pH 5.0 to 6.0. Sodium azide and fluoride strongly inhibited L95-1 activity, whereas sulphate salts inhibited weakly. The laccase was immobilized on the Fe3O4 nanoparticles and characterized. Residual activity remained at 20% after ten cycles of ABTS oxidation reaction. The immobilized laccase showed higher tolerance to various metal salts. The properties of L95-1 laccase make it potentially useful in the biotechnological applications.

scholarly journals Synthesis and Bioactivity of Quinone Mono- and Dioxime Salts

2020 ◽  
Vol 10 (5) ◽  
pp. 6148-6156
Keyword(s):  
Alkali Metal ◽  
Phytophthora Infestans ◽  
Metal Salt ◽  
Human Life ◽  
Alkali Metal Hydroxide ◽  
Divalent Metal ◽  
Metal Salts ◽  
Zinc Salts ◽  
Harmful Organisms ◽  
Two Stages

Eliminating all kinds of harmful organisms is an important task in agriculture, food production, and human life. Quinone oximes and their salts are good bioactive compounds to attain this aim. The alkali metal salts of quinone mono- and dioxime have been synthesized by the reaction of the corresponding quinone oxime with alkali metal hydroxide. The divalent metal salts have been obtained in two stages. The first stage is the synthesis of the sodium salt of the quinone oxime. The second step is the reaction of the latter with a divalent metal salt. Copper and zinc salts of [(4-oxocyclohexa-2,5-dien-1-ylidene)amino]oxidanide have the highest insecticidal activity against the housefly and rice weevil. The death index is 90–100%. Copper {[2-methyl-4-oxo-5-(propan-2-yl)cyclohexa-2,5-dien-1-ylidene]amino}oxidanide shows good activity against Phytophthora infestans. Inhibition of the growth and development of the Phytophthora infestans is 80%.

scholarly journals Catalytic Conversion of Carbon Dioxide through C-N Bond Formation

Molecules ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 182 ◽  
Author(s):  
Jing-Yuan Li ◽  
Qing-Wen Song ◽  
Kan Zhang ◽  
Ping Liu
Keyword(s):  
Carbon Dioxide ◽  
Catalytic Mechanism ◽  
Bond Formation ◽  
Catalytic Efficiency ◽  
Chemical Fixation ◽  
Catalytic Systems ◽  
Formation Reaction ◽  
Metal Free ◽  
The Past ◽  
Regulatory Strategies

From the viewpoint of green chemistry and sustainable development, it is of great significance to synthesize chemicals from CO2 as C1 source through C-N bond formation. During the past several decade years, many studies on C-N bond formation reaction were involved, and many efforts have been made on the theory. Nevertheless, several great challenges such as thermodynamic limitation, low catalytic efficiency and selectivity, and high pressure etc. are still suffered. Herein, recent advances are highlighted on the development of catalytic methods for chemical fixation of CO2 to various chemicals through C-N bond formation. Meanwhile, the catalytic systems (metal and metal-free catalysis), strategies and catalytic mechanism are summarized and discussed in detail. Besides, this review also covers some novel synthetic strategies to urethanes based on amines and CO2. Finally, the regulatory strategies on functionalization of CO2 for N-methylation/N-formylation of amines with phenylsilane and heterogeneous catalysis N-methylation of amines with CO2 and H2 are emphasized.

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