scholarly journals Hexavalent Chromate Reductase Activity in Cell Free Extracts ofPenicilliumsp.

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Damaris L. Arévalo-Rangel ◽  
Juan F. Cárdenas-González ◽  
Víctor M. Martínez-Juárez ◽  
Ismael Acosta-Rodríguez
Keyword(s):  
Metal Ions ◽  
Hexavalent Chromium ◽  
Electron Donor ◽  
Reductase Activity ◽  
Electron Donors ◽  
Cell Free Extract ◽  
Optimal Temperature ◽  
Chromate Reductase

A chromium-resistant fungus isolated from contaminated air with industrial vapors can be used for reducing toxic Cr(VI) to Cr(III). This study analyzes in vitro reduction of hexavalent chromium using cell free extract(s) of the fungus that was characterized based on optimal temperature, pH, use of electron donors, metal ions and initial Cr(VI) concentration in the reaction mixture. This showed the highest activity at 37°C and pH 7.0; there is an increase in Cr(VI) reductase activity with addition of NADH as an electron donor, and it was highly inhibited by Hg2+, Ca2+and Mg2+, and azide, EDTA, and KCN.

In vitro reduction of hexavalent chromium by a cell-free extract of Bacillus sp. ES 29 stimulated by Cu 2+

2003 ◽  
Vol 62 (5-6) ◽  
pp. 569-573 ◽  
Author(s):  
F. A. O. Camargo ◽  
B. C. Okeke ◽  
F. M. Bento ◽  
W. T. Frankenberger
Keyword(s):  
Hexavalent Chromium ◽  
Bacillus Sp ◽  
Cell Free Extract ◽  
A Cell

scholarly journals Chromate Reduction by Cell-Free Extract of Bacillus firmus KUCr1

2010 ◽  
Vol 59 (3) ◽  
pp. 185-190 ◽  
Author(s):  
GOPI BALLAV SAU ◽  
SWAGATA CHATTERJEE ◽  
SAMIR KUMAR MUKHERJEE
Keyword(s):  
Enzyme Activity ◽  
Reductase Activity ◽  
Enzyme Concentration ◽  
Metabolic Inhibitor ◽  
Chromate Reduction ◽  
Cell Free Extract ◽  
Bacillus Firmus ◽  
Soluble Cell ◽  
Enzymatic Reduction

Microbial enzymatic reduction of a toxic form of chromium [Cr(VI)] has been considered as an effective method for bioremediation of this metal. This study reports on the in vitro reduction of Cr(VI) using cell-free extracts from a Cr(VI) reducing Bacillus firmus KUCr1 strain. Chromium reductase was found to be constitutive and its activity was observed both in soluble cell fractions (S12 and S150 and membrane cell fraction (P150). The reductase activity of S12 fraction was found to be optimal at 40 microM Cr(VI) with enzyme concentration equivalent to 0.493 mg protein/ml. Enzyme activity was dependent on NADH or NADPH as electron donor; optimal temperature and pH for better enzyme activity were 70 degrees C and 5.6, respectively. The Km value of the reductase was 58.33 microM chromate having a V(max) of 11.42 microM/min/mg protein. The metabolic inhibitor like sodium azide inhibited reductase activity of membrane fraction of the cell-free extract. Metal ions like Cu2+, Co2+, Ni2+ and As3+ stimulated the enzyme but others, such as Ag+, Hg2+, Zn2+, Mn2+, Cd2+ and Pb2+, inhibited Cr(VI) reductase activity.

scholarly journals Hydroxylamine Reductase Activity of the Hybrid Cluster Protein from Escherichia coli

2002 ◽  
Vol 184 (21) ◽  
pp. 5898-5902 ◽  
Author(s):  
Marcus T. Wolfe ◽  
Jongyun Heo ◽  
John S. Garavelli ◽  
Paul W. Ludden
Keyword(s):  
Escherichia Coli ◽  
Nitrogen Metabolism ◽  
Reductase Activity ◽  
Spectroscopic Properties ◽  
Electron Donors ◽  
Hybrid Cluster ◽  
Enzymatic Function ◽  
Spectroscopic Characteristics ◽  
Biochemical Analyses

ABSTRACT The hybrid cluster protein (HCP; formerly termed the prismane protein) has been extensively studied due to its unique spectroscopic properties. Although the structural and spectroscopic characteristics are well defined, its enzymatic function, up to this point, has remained unidentified. While it was proposed that HCP acts in some step of nitrogen metabolism, a specific role for this enzyme remained unknown. Recent studies of HCP purified from Escherichia coli have identified a novel hydroxylamine reductase activity. These data reveal the ability of HCP to reduce hydroxylamine in vitro to form NH3 and H2O. Further biochemical analyses were completed in order to determine the effects of various electron donors, different pH levels, and the presence of CN− on in vitro hydroxylamine reduction.

Nitrate Reductase from Sphagnum Species: Isolation, in vitro Assays and Partial Purification

1987 ◽  
Vol 42 (5) ◽  
pp. 653-656 ◽  
Author(s):  
Holger Deising
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reductase Activity ◽  
Reductase Activity ◽  
Affinity Purification ◽  
Electron Donors ◽  
In Vitro Assays ◽  
Partial Purification ◽  
Blue Sepharose ◽  
Species Isolation

Nitrate reductase (EC 1.6.6.2) has been isolated from 11 Sphagnum (Bryophyta) species and purified up to 500-fold by a procedure involving (NH4)2SO4 precipitation and blue sepharose affinity chromatography. The purest fraction showed a nitrate reductase activity of 7.7 nkat mg protein-1 with NADPH as the electron donor. Beside NADPH and NADH, FMNH2 and - after blue sepharose affinity purification of the enzyme - MVH2 were used as electron donors in different assays.

scholarly journals Electron transfer to nitrite reductase of Rhodobacter sphaeroides 2.4.3: examination of cytochromes c 2 and c Y

Microbiology ◽  
2006 ◽  
Vol 152 (5) ◽  
pp. 1479-1488 ◽  
Author(s):  
William P. Laratta ◽  
Michael J. Nanaszko ◽  
James P. Shapleigh
Keyword(s):  
Electron Transfer ◽  
Electron Donor ◽  
Rhodobacter Sphaeroides ◽  
Nitrite Reductase ◽  
Double Mutant ◽  
Reductase Activity ◽  
Nitrite Reduction ◽  
Nitrite Reductase Gene ◽  
Nitrite Reductase Activity

The role of cytochrome c 2, encoded by cycA, and cytochrome c Y, encoded by cycY, in electron transfer to the nitrite reductase of Rhodobacter sphaeroides 2.4.3 was investigated using both in vivo and in vitro approaches. Both cycA and cycY were isolated, sequenced and insertionally inactivated in strain 2.4.3. Deletion of either gene alone had no apparent effect on the ability of R. sphaeroides to reduce nitrite. In a cycA–cycY double mutant, nitrite reduction was largely inhibited. However, the expression of the nitrite reductase gene nirK from a heterologous promoter substantially restored nitrite reductase activity in the double mutant. Using purified protein, a turnover number of 5 s−1 was observed for the oxidation of cytochrome c 2 by nitrite reductase. In contrast, oxidation of c Y only resulted in a turnover of ∼0·1 s−1. The turnover experiments indicate that c 2 is a major electron donor to nitrite reductase but c Y is probably not. Taken together, these results suggest that there is likely an unidentified electron donor, in addition to c 2, that transfers electrons to nitrite reductase, and that the decreased nitrite reductase activity observed in the cycA–cycY double mutant probably results from a change in nirK expression.

Synthesis, Spectral and Antimicrobial Investigation of 2-(Naphthalenel-ylamino)-2- Phenylacetonitrile and 1, 10-Phenanthroline with Five Divalent Transition Metal Ions

2019 ◽  
Vol 10 (01) ◽  
Author(s):  
Mohammed Al-Amery1 ◽  
Ashraf Saad Rasheed ◽  
Dina A. Najeeb
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Transition Metal Ions ◽  
Molar Conductance ◽  
Octahedral Geometry ◽  
Mixed Ligand ◽  
Gram Negative Bacteria ◽  
Magnetic Studies ◽  
Gram Positive Bacteria

Five new mixed ligand metal complexes have been synthesized by the reaction of divalent transition metal ions (Hg, Ni, Zn, Cu and Cd) with 2-(naphthalen-l-ylamino)-2-phenylacetonitrile (L1 ) and 1,10-phenanthroline (L2). The coordination likelihood of the two ligands toward metal ions has been suggested in the light of elemental analysis, UV-Vis spectra, FTIR, 1H-NMR, flam atomic absorption, molar conductance and magnetic studies. Results data suggest that the octahedral geometry for all the prepared complexes. Antibacterial examination of synthesized complexes in vitro was performed against four bacterias. Firstly, Gram-negative bacteria namely, Pseudomonas aerugin and Escherichia. Secondly, Gram-positive bacteria namely, Bacillus subtilis, Staphylococcuaurouss. Results data exhibit that the synthesized complexes exhibited more biological activity than tetracycline pharmaceutical.

Synthesis, Characterization and in vitro Biological Evaluation of a New Schiff Base Derived from Drug and its Complexes with Transition Metal Ions

2018 ◽  
Vol 69 (7) ◽  
pp. 1678-1681
Author(s):  
Amina Mumtaz ◽  
Tariq Mahmud ◽  
M. R. J. Elsegood ◽  
G. W. Weaver
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Free Ligand ◽  
Transition Metal Ions ◽  
Biological Evaluation ◽  
Pyridoxal Hydrochloride

New series of copper (II), cobalt (II), zinc (II), nickel (II), manganese (II), iron (II) complexes of a novel Schiff base were prepared by the condensation of sulphadizine and pyridoxal hydrochloride. The ligand and metal complexes were characterized by utilizing different instrumental procedures like microanalysis, thermogravimetric examination and spectroscopy. The integrated ligand and transition metal complexes were screened against various bacteria and fungus. The studies demonstrated the enhanced activity of metal complexes against reported microbes when compared with free ligand.

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