scholarly journals Characterization of Metal Chelation with a Mutagenic Agent, 5-Bromouracil

1990 ◽  
Vol 63 (4) ◽  
pp. 1226-1229 ◽  
Author(s):  
Udai P. Singh ◽  
Ranjana Ghose ◽  
Animesh K. Ghose
Keyword(s):  
Metal Chelation ◽  
Mutagenic Agent

Expression and Characterization of Recombinant Drosophila 6-pyruvoyl tetrahydropterin Synthase

Pteridines ◽  
1995 ◽  
Vol 6 (2) ◽  
pp. 58-62
Author(s):  
Young Shik Park ◽  
Nacksung Kim ◽  
Hajeong Kim ◽  
Dongkook Park ◽  
Jeongbin Yim
Keyword(s):  
Recombinant Protein ◽  
Isoelectric Point ◽  
Crude Extract ◽  
Fusion Proteins ◽  
Heat Stability ◽  
Native Enzyme ◽  
Metal Chelation ◽  
E Coli ◽  
Metal Chelating

Summary 6-Pyruvoyl tetrahydropterin synthase is involved in the synthesis of pteridine eye pigments in Drosophila. The purple gene which was known to be one of the target loci of the suppressor mutation su(sj2 has been identified to encode the enzyme, and its cDNA has been cloned recently. The cDNA encoding the 19.3 kDa subunit of the 6-pyruvoyl tetrahydropterin synthase was expressed as fusion proteins in E. coli. The recombinant protein was shown to be active and purified from the E. coli crude extract by metal-chelation chromatography. The fused metal-chelating oilgopeptide was removed by thrombin for further characterization. Apparent Km for the substrate dihydroneopterin triphosphate was determined to be 590 IlM, which was slightly higher than the value of the native enzyme. The isoelectric point of 6.4 was also different from the known value of 4.3 determined by the native enzyme. Heat stability and the stimulatory effect of reducing agents were similar to the native enzyme. The modification of cysteine residues in the recombinant enzyme, one of which is known to be conserved in human and rat enzymes, by iodoacetamide inhibited its activity by up to 80%.

scholarly journals Characterization and Stability of the Antimony-Quercetin Complex

2019 ◽  
Vol 9 (3) ◽  
pp. 432-438 ◽  
Author(s):  
Valcilaine Teixeira Barbosa ◽  
Janaína Barros de Menezes ◽  
Josué Carinhanha Caldas Santos ◽  
Maria Lysete de Assis Bastos ◽  
João Xavier de Araújo-Júnior ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Metal Chelation ◽  
X Ray Diffraction ◽  
Future Studies ◽  
Potassium Tartrate ◽  
Shoulder Peak ◽  
Ft Ir ◽  
Therapeutic Properties ◽  
Relationship Of

Purpose: Quercetin is a flavonoid known for its therapeutic properties and for forming complexes. Although the antimony-quercetin (SbQ) complex has been produced before, no previous exploration of its characteristics has been published in literature. Thus, this study aimed to characterize this complex, assess its stability and investigate its complexation site through its antibacterial activity. Methods: The SbQ complex was synthetized using Sb(III) potassium tartrate trihydrate and quercetin anhydrous (1:1) (v/v) as a solution and dried using three methods: rotaevaporation, lyophilization and spray drying. The material, in solution, was analyzed by UV-vis and fluorimetry; and, in the powder, by X-ray diffraction (XRD), both scanning electronic and fluorescence microscopy and infrared spectroscopy (FT-IR). Antimicrobial activity was evaluated via broth microdilution. Results: UV-vis exhibited a shoulder peak at 291 nm indicating metal chelation at C-ring of quercetin and confirmed 1:1 stoichiometry. Spectrofluorimetry showed an increase of intensity with the complex formation with an emission band (525 nm). After drying, XRD and SEM indicated loss of crystallinity and a difference in shape and size of the complex compared to its precursors. FT-IR suggested by a shift of frequency of the carbonyl group (1661 cm-1) that the quercetin bond to antimony by the C-3, followed by positions C-5 and C-4 carbonyl, which has been confirmed by MIC through the structure-activity relationship of the antibacterial activity of quercetin. Conclusion: These results provided a characterization of SbQ complex with the confirmation of its binding site, working as a guide for future studies involving this complex.

scholarly journals Synthesis and Cytoprotective Characterization of 8-Hydroxyquinoline Betti Products

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1934 ◽  
Author(s):  
Iván Kanizsai ◽  
Ramóna Madácsi ◽  
László Hackler ◽  
Márió Gyuris ◽  
Gábor J. Szebeni ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Gene Expression Analysis ◽  
Aromatic Aldehydes ◽  
Primary Amines ◽  
Metal Chelation ◽  
Future Studies ◽  
Cytoprotective Activity ◽  
Chemically Induced

The 8-hydroxyquinoline pharmacophore scaffold has been shown to possess a range of activities as metal chelation, enzyme inhibition, cytotoxicity, and cytoprotection. Based on our previous findings we set out to optimize the scaffold for cytoprotective activity for its potential application in central nervous system related diseases. A 48-membered Betti-library was constructed by the utilization of formic acid mediated industrial-compatible coupling with sets of aromatic primary amines such as anilines, oxazoles, pyridines, and pyrimidines, with (hetero)aromatic aldehydes and 8-hydroxiquinoline derivatives. After column chromatography and re-crystallization, the corresponding analogues were obtained in yields of 13–90%. The synthesized analogs were optimized with the utilization of a cytoprotection assay with chemically induced oxidative stress, and the most active compounds were further tested in orthogonal assays, a real time cell viability method, a fluorescence-activated cell sorting (FACS)-based assay measuring mitochondrial membrane potential changes, and gene expression analysis. The best candidates showed potent, nanomolar activity in all test systems and support the need for future studies in animal models of central nervous system (CNS) disorders.

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