Competition among Metal Ions for Protein Binding Sites: Determinants of Metal Ion Selectivity in Proteins

2013 ◽  
Vol 114 (1) ◽  
pp. 538-556 ◽  
Author(s):  
Todor Dudev ◽  
Carmay Lim
Keyword(s):  
Protein Binding ◽  
Metal Ions ◽  
Binding Sites ◽  
Metal Ion ◽  
Ion Selectivity ◽  
Protein Binding Sites ◽  
Metal Ion Selectivity

How an electric field can modulate the metal ion selectivity of protein binding sites: insights from DFT/PCM calculations

2018 ◽  
Vol 20 (38) ◽  
pp. 24633-24640 ◽  
Author(s):  
Todor Dudev ◽  
Sonia Ilieva ◽  
Lyudmila Doudeva
Keyword(s):  
Electric Field ◽  
Protein Binding ◽  
Binding Site ◽  
Binding Sites ◽  
Metal Ion ◽  
Ion Selectivity ◽  
Protein Binding Site ◽  
Protein Binding Sites ◽  
Metal Selectivity ◽  
Metal Ion Selectivity

An electric field (internal or external) is a potent force that can modulate the metal selectivity of a protein binding site.

scholarly journals STUDY OF REMOVAL OF METAL IONS IN WATER USING ZEOLITES SYNTHESIZED WITH CHARCOAL ASHES

2006 ◽  
Vol 05 (3) ◽  
pp. 21-30
Author(s):  
Denise Alves FUNGARO ◽  
Juliana de Carvalho IZIDORO
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Ion Selectivity ◽  
Coal Ash ◽  
Electroplating Effluent ◽  
Zeolitic Material ◽  
Equilibrium Data ◽  
Metal Ion Selectivity ◽  
Removal Of Metal ◽  
Removal Of Metal Ions

The capacity of synthesized zeolites from Brazilian coal ash for the removal of metal ions from aqueous solutions has been investigated. Equilibrium data obtained have been found to fit both the Langmuir and Freundlich adsorption isotherms. The zeolitic material prepared with coal ash from baghouse filter showed the highest removal efficiencies. The metal ion selectivity of this product was determined as: Pb2+ > Cd2+ > Cu2+ > Zn2+ > Ni2+. The maximum cation exchange capacities were between 32.9 and 246.9 mg g-1. Tests showed that the zeolitic material was suitable for removal of zinc from electroplating effluent.

scholarly journals Metal Ion Selectivity of Kojate Complexes: A Theoretical Study

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Sarita Singh ◽  
Jyoti Singh ◽  
Sunita Gulia ◽  
Rita Kakkar
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Density Functional ◽  
Ion Selectivity ◽  
Divalent Metal Ions ◽  
High Energies ◽  
Square Planar ◽  
Metal Ion Selectivity ◽  
Carbonyl Bond ◽  
Complexation Reactions

Density functional calculations have been performed on four-coordinate kojate complexes of selected divalent metal ions in order to determine the affinity of the metal ions for the kojate ion. The complexation reactions are characterized by high energies, showing that they are highly exothermic. It is found that Ni(II) exhibits the highest affinity for the kojate ion, and this is attributed to the largest amount of charge transfer from the ligand to the metal ion. The Ni(II) complex has distorted square planar structure. The HOMOs and LUMOs of the complexes are also discussed. All complexes display a strong band at ~1500 cm−1 corresponding to the stretching frequency of the weakened carbonyl bond. Comparison of the complexation energies for the two steps shows that most of the complexation energy is realized in the first step. The energy released in the second step is about one-third that of the first step.

scholarly journals Host–Guest Extraction of Heavy Metal Ions with p-t-Butylcalix[8]arene from Ammonia or Amine Solutions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Md. Hasan Zahir ◽  
Shakhawat Chowdhury ◽  
Md. Abdul Aziz ◽  
Mohammad Mizanur Rahman
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Ion Selectivity ◽  
Ammonia Solution ◽  
Ethylene Diamine ◽  
Variation Method ◽  
Extraction Behavior ◽  
Metal Ion Selectivity

The capacities of the p-t-butylcalix[8]arene (abbreviated as H8L) host to extract toxic divalent heavy metal ions and silver from aqueous solution phases containing ammonia or ethylene diamine to an organic phase (nitrobenzene, dichloromethane, or chloroform) were carried out. When the metal ions were extracted from an aqueous ammonia solution, the metal ion selectivity for extraction was found to decrease in the order Cd2+> Ni2+> Cu2+> Ag+> Co2+> Zn2+. When the aqueous phase contained ethylene diamine, excellent extraction efficiencies of 97% and 90% were observed for the heavy metal ions Cu2+ and Cd2+, respectively. Under the same conditions the extraction of octahedral type metal ions, namely, Co2+ and Ni2+, was suppressed. The extraction of transition metal cations by H8L in ammonia and/or amine was found to be pH dependent. Detailed analysis of extraction behavior was investigated by slope analysis, the continuous variation method, and by loading tests.

EVALUATION OF TISSUE STEROID BINDING IN VITRO

1971 ◽  
Vol 68 (1_Suppl) ◽  
pp. S223-S246 ◽  
Author(s):  
C. R. Wira ◽  
H. Rochefort ◽  
E. E. Baulieu
Keyword(s):  
Protein Binding ◽  
Binding Sites ◽  
Experimental System ◽  
Specific Protein ◽  
Coupling Mechanism ◽  
Target Tissue ◽  
Protein Binding Sites ◽  
Definition Of ◽  
Hormone Specificity

ABSTRACT The definition of a RECEPTOR* in terms of a receptive site, an executive site and a coupling mechanism, is followed by a general consideration of four binding criteria, which include hormone specificity, tissue specificity, high affinity and saturation, essential for distinguishing between specific and nonspecific binding. Experimental approaches are proposed for choosing an experimental system (either organized or soluble) and detecting the presence of protein binding sites. Techniques are then presented for evaluating the specific protein binding sites (receptors) in terms of the four criteria. This is followed by a brief consideration of how receptors may be located in cells and characterized when extracted. Finally various examples of oestrogen, androgen, progestagen, glucocorticoid and mineralocorticoid binding to their respective target tissues are presented, to illustrate how researchers have identified specific corticoid and mineralocorticoid binding in their respective target tissue receptors.

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