scholarly journals Mechanism of ligand binding to α1-acid glycoprotein (orosomucoid): correlated thermodynamic factors and molecular parameters of polarity

1995 ◽  
Vol 306 (2) ◽  
pp. 545-549 ◽  
Author(s):  
S Urien ◽  
Y Giroud ◽  
R S Tsai ◽  
P A Carrupt ◽  
F Brée ◽  
...  
Keyword(s):  
Binding Sites ◽  
Partition Coefficients ◽  
Water Systems ◽  
Hydrogen Bond Donor ◽  
Acid Glycoprotein ◽  
Number Of Binding Sites ◽  
Modelling Techniques ◽  
Polar Interactions ◽  
Polarity Parameters

Eight ligands were used in this study, four basic, three neutral and one acidic. Their binding to serum alpha 1-acid glycoprotein (orosomucoid) was measured at several temperatures, and the data were analysed together by a general model with three unknowns, number of binding sites, delta H0 and delta S0. The partition coefficients of the ligands were measured in octanol/water and heptane/water systems (log Poct. and log Phep.), and their molecular volumes were calculated by molecular modelling techniques. These structural properties allow determination of polarity parameters (delta log Poct.-hep., lambda oct. and lambda hep.) which encode in different proportions the various polar interactions between the solute and the aqueous and organic phases, i.e. hydrogen-bonding capacity and dipolarity/polarizability. This study shows that good correlations exist between delta H0 or delta S0 and polarity parameters, such that the enthalpic contribution to binding increases with increasing polarity of the ligands, mainly hydrogen-bond-donor acidity, whereas their entropic contribution to binding decreases.

Determination of Conformer-Specific Partition Coefficients in Octanol/Water Systems

2003 ◽  
Vol 46 (11) ◽  
pp. 2241-2245 ◽  
Author(s):  
Márta Kraszni ◽  
István Bányai ◽  
Béla Noszál
Keyword(s):  
Partition Coefficients ◽  
Water Systems

scholarly journals Determination of the Binding Parameters between Proteins and Luminol by Chemiluminescence Using Flow Injection Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Jie Guo ◽  
Donghua Chen ◽  
Zhenghua Song
Keyword(s):  
Bovine Serum Albumin ◽  
Flow Injection ◽  
Binding Sites ◽  
Bovine Serum ◽  
Binding Constants ◽  
Injection Technique ◽  
Binding Parameters ◽  
Hydrophobic Force ◽  
Number Of Binding Sites

The interaction behavior of bovine serum albumin (BSA), lysozyme (LYS), myoglobin (MB), and catalase (CAT) with luminol, respectively, was first studied by chemiluminescence (CL) using flow injection (FI) technique based on the fact that the studied proteins can enhance the CL intensity of luminol. A FI-CL model of protein-luminol interaction, lg[(I0−I)/I]=1/nlg[P]+1/nlgKa+2lgn, was constructed, and the interaction parameters of BSA, LYS, MB, and CAT with luminol were determined accordingly. The binding constants Ka are in the descending order of CAT > MB > LYS > BSA at the level of 105 to 107 L mol−1, and the number of binding sites n of luminol to BSA or LYS is around 2 and to MB or CAT is around 1. The results of thermodynamic parameters (ΔH, ΔS, and ΔG) showed that the binding processes of luminol to the four proteins are spontaneous mainly through the hydrophobic force.

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