Ternary Transition Metal Complexes with an Azo-Imine Ligand and 2,2'-Bipyridine: Characterization, Computational Calculations, and Acetylcholinesterase Inhibition Activities.

New mononuclear ternary transition metal complexes: [M(HL)(bipy)2]ClO4, (M: Mn(II) for 1, Ni(II) for 2), [M(HL)(bipy) (ClO4)], (M: Ni(II) for 3, Cu(II) for 4, Zn(II) for 5) with M(II), 2-[(E)-(hydroxyimino)methyl]-4-[(E)-phenyldiazenyl]phenol, H2L, and 2,2'-bipyridine were synthesized. The structures of the complexes were investigated by using various analytical, spectroscopic techniques such as elemental analysis, FTIR, UV-Vis, NMR, MALDI-TOF mass spectrometry, thermal analysis, and computational studies containing geometric optimizations and theoretical calculations of vibrations and electronic transitions. IR and thermal analysis data verifies the proposed structure of the complexes. The inhibition activities of the complexes against acetylcholinesterase (AChE) extracted from Ricania simulans adults and nymphs were examined and all the complexes were found to be active. Among the complexes studied, the most inhibition activity was exhibited by complex 5 with the lowest IC50 value (3.2±0.8) for AChE of adults, complex 3 with the lowest IC50 value (4.6±0.8) for AChE of nymphs.

Characterization and inhibition studies of carbonic anhydrase from gill of Russian Sturgeon Fish (Acipenser gueldenstaedtii).

An α-carbonic anhydrase (CA, EC 4.2.1.1) was purified and characterized kinetically from gill of Acipenser gueldenstaedtii as an endangered sturgeon species. The carbonic anhydrase was purified 66-folds with yield 20.7% by Sepharose-4B-l-tyrosine-sulfanilamide affinity column and the specific activity was determined as 222.2 EU/mg protein. Km and Vmax kinetic values for gill carbonic anhydrase were calculated by a Lineweaver-Burk graph using p-nitrophenol acetate (p-NPA) as a substrate, and was defined as 2.5 mM and 5 × 10(6 )µM/min, respectively. It was observed that CA from the sturgeon gill in the presence of the sulfanilamide and acetazolamide as an inhibitor had very low IC50 values such as 13.0 and 0.1 µM, respectively. In addition, it was determined that the enzyme was inhibited by Fe(2+,) Co(2+,) Ni(2+), and Zn(2+)-Ba(2+) with the IC50 values of 0.2, 1.7, 1.2, and 1.1 mM, respectively.

Partial purification and characterization of lipase from Geobacillus stearothermophilus AH22.

The lipase was partially purified by ion exchange chromatography and gel filtration column chromatography, and was characterized from Geobacillus stearothermophilus AH22 strain. The lipase was purified 18.3-folds with 19.7% recovery. The lipase activity was determined by using p-nitrophenyl esters (C2-C12) as substrates. The Km values of the enzyme for these substrates were found as 0.16, 0.02, 0.19 and 0.55 mM, respectively, while Vmax values were 0.52, 1.03, 0.72 and 0.15 U mg(-1). The enzyme showed maximum activity at 50 °C and between pH 8.0 and 9.0. The enzyme was found to be quite stable at pH range of 4.0-10.0, and thermal stability between 50 and 60 °C. It was found that the best inhibitory effect of the enzyme activity was of Hg(2+). The inhibitory effect as orlistat, catechin, propyl paraben, p-coumaric acid, 3,4-dihydroxy hydro-cinnamic acid was examined. These results suggest that G. stearothermophilus AH22 lipase presents very suitable properties for industrial applications.

Purification and characterization of extracellular α-amylase from a thermophilic Anoxybacillus thermarum A4 strain

ABSTRACT α-Amylase from Anoxybacillus thermarum A4 was purified using ammonium sulphate precipitation and Sephadex G-100 gel filtration chromatography, with 29.8-fold purification and 74.6% yield. A4 amylase showed best performance for soluble potato starch hydrolysis at 70 °C and pH 5.5-10.5. A4 amylase was extremely stable at +4 °C, and the enzyme retained over 65% of its original α-amylase activity at 70 °C and 43% at 90 °C. The enzyme's Km values for soluble starch, amylopectin and amylose substrates were obtained as 0.9, 1.3 and 0.5 mg/mL, respectively. EDTA, Hg2+, B4O7 2-, OH-, CN- , and urea exhibited different inhibition effects; their IC50 values were identified as 8.0, 5.75, 16.5, 15.2, 8.2 and 10.9 mM, respectively. A4 amylase exhibited extreme stability toward some surfactants and perfect match for a wide variety of commercial solid and liquid detergents at 55 °C. So, it may be considered to be potential applications for detergent and other industrial uses.

Polyphenol oxidase activity and antioxidant properties of Yomra apple (Malus communis L.) from Turkey.

In this study, firstly, antioxidant and polyphenol oxidase (PPO) properties of Yomra apple were investigated. Seventeen phenolic constituents were measured by reverse phase-high-performance liquid chromatography (RP-HPLC). Total phenolic compounds (TPCs), ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activities were performed to measure antioxidant capacity. Some kinetic parameters (Km, Vmax), and inhibition behaviors against five different substrates were measured in the crude extract. Catechin and chlorogenic acid were found as the major components in the methanolic extract, while ferulic acid, caffeic acid, p-hydroxybenzoic acid, quercetin and p-coumaric acid were small quantities. Km values ranged from 0.70 to 10.10 mM in the substrates, and also 3-(4-hydroxyphenyl) propanoic acid (HPPA) and L-DOPA showed the highest affinity. The inhibition constant of Ki were ranged from 0.05 to 14.90 mM against sodium metabisulphite, ascorbic acid, sodium azide and benzoic acid, while ascorbic acid and sodium metabisulphite were the best inhibitors.

Characterization and inhibition studies of an α-carbonic anhydrase from the endangered sturgeon species Acipenser gueldenstaedti.

An α-carbonic anhydrase (CA, EC 4.2.1.1) was purified and characterized kinetically from erythrocytes of the sturgeon Acipenser gueldenstaedti, an endangered species. The sturgeon enzyme (AgCA) showed kinetic parameters for the CO(2) hydration reaction comparable with those of the human erythrocytes enzyme hCA II, being a highly active enzyme, whereas its esterase activity with 4-nitrophenyl acetate as substrate was lower. Sulphonamide inhibitors (acetazolamide, sulphanilamide) strongly inhibited AgCA, whereas metal ions (Ag(+), Zn(2+), Cu(2+) and Co(2+)) were weak, millimolar inhibitors. Several widely used pesticides (2,4-dichlorophenol, dithiocarbamates, parathion and carbaryl) were also assayed as inhibitors of this enzyme. The dithiocarbamates were low micromolar AgCA inhibitors (IC(50) of 16-18 µM), whereas the other pesticides inhibited the enzyme with IC(50)s in the range of 102-398 µM. The wide use of dithiocarbamate pesticides may be one of the factors enhancing the vulnerability of this sturgeon species to pollutants.

Chemical and antioxidant properties of Laurocerasus officinalis Roem. (cherry laurel) fruit grown in the Black Sea region.

Laurocerasus officinalis Roem. is a summer fruit highly characteristic of the Black Sea region. The edible parts of the fruit were tested for chemical composition and antioxidant properties. Total moisture, ash, protein, sugar, pectin, ascorbic acid, phenolic, and mineral contents of the fruit were determined. The antioxidant activity of the fruit was investigated using TLC plate and ferric thiocyanate methods. Its antioxidative character was also tested utilizing hydroxyl, DPPH, and superoxide radical scavenging activity measurements, using BHT, vitamin C, and Trolox as references. Besides being a good source of nutrients, L. officinalis was found to provide a rich source of protective antioxidant compounds. Its antioxidant and radical scavenging activities were comparable to or higher than those of the reference antioxidants. It appeared to have high mineral content. The concentrations of macroelements K, Mg, Ca, and Na were high at 2215 +/- 10.5, 179 +/- 11, 153 +/- 0.8, and 55 +/- 0.3 mg/kg, respectively, and the concentrations of trace elements Mn, Fe, Zn, and Cu were 24.2 +/- 1.3, 8.3 +/- 0.8, 1.9 +/- 0.2, and 0.8 +/- 0.1 mg/kg, respectively. In addition, the fruit showed very low contents of Pb, Ni, Co, and Cr, below the detection limits, which is considered to be a good food quality. As it is a rich source of protein, sugar, ascorbic acid, minerals, and antioxidants, L. officinalis is well worth further studies regarding its components possessing important health benefits and inclusion in the daily diet.