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Analysis of oxygen binding by hemoglobin on the basis of mean intrinsic thermodynamic quantities

100%

Bordbar A.-K., Mousavi S. H.-A., Dazhampanah H.

2006

vol. 53

issue 3

563-568

The binding data for oxygenation of human hemoglobin, Hb, at various temperatures and in the absence and presence of 2,3-diphosphoglycerate, DPG, and inositol hexakis phosphate, IHP, were analyzed for extraction of mean intrinsic Gibbs free energy, ΔGo, enthalpy, ΔHo, and entropy, ΔSo, of binding at various partial oxygen pressures. This method of analysis considers all the protein species present such as dimer and tetramer forms which were not considered by Imai et al. (Imai K et al., 1970, Biochim Biophys Acta 200: 189 - 196) , in their analysis which was based on Adair equation. In this regard, the values of Hill equation parameters were estimated with high precision at all points of the binding curve and used for calculation of ΔGo, ΔHo and ΔSo were also calculated by analysis of ΔGo values at various temperatures using van't Hoff equation. The results represent the enthalpic nature of the cooperativity in Hb oxygenation and the compensation effect of intrinsic entropy. The interpretation of results also to be, into account the decrease of the binding affinity of sites for oxygen in the presence of DPG and IHP without any considerable changes in the site - site interaction (extent of cooperativity). In other words, the interactions between bound ligands, organic phosphates and oxygen, are more due to a decreasing binding affinity and not to the reduction of the cooperative interaction between sites. The results also document the more heterotropic effect of IHP compared to DPG.

Effects of low doses of gamma rays on the stability of normal and diabetic erythrocytes

75%

Kaczmarska M., Kopyściańska Z., Fornal M., Grodzicki T., Matlak K., Korecki J., Burda K.

2011

vol. 58

issue 4

489-496

We studied the influence of low doses of γ radiation (from 0.04 to 1.8 mGy) on the stability of human red blood cells (RBC) from healthy donors and diabetic patients using absorption spectroscopy. Because of the alteration of many enzymatic pathways in diabetic RBCs resulting in strong modification of the lipid and protein membrane components one could expect that the ionizing γ-radiation should influence the stability of the healthy and diabetic cells in a different way. Indeed, distinct discontinuities and monotonic changes of hemolysis detected in the healthy and diabetic RBCs suggest that various enzymatic and chemical processes are activated in these membranes by γ radiation. Mössbauer measurements showed that only the highest applied dose of γ radiation caused modification of hemoglobin in both types of RBCs.

New generation of peptide antibiotics

63%

Dubin A., Mak P., Dubin G., Rzychon M., Stec-Niemczyk J., Wladyka B., Maziarka K., Chmiel D.

2005

vol. 52

issue 3

633-638

The increasing antibiotic resistance of pathogenic bacteria calls for the development of alternative antimicrobial strategies. Possible approaches include the development of novel, broad-spectrum antibiotics as well as specific targeting of individual bacterial virulence factors. It is impossible to decide currently which strategy will prove more successful in the future since they both promise different advantages, but also introduce diverse problems. Considering both approaches, our laboratory's research focuses on the evaluation of hemocidins, broad-spectrum antibacterial peptides derived from hemoglobin and myoglobin, and staphostatins, specific inhibitors of staphopains - Staphylococcus aureus secreted proteases that are virulence factors regarded as possible targets for therapy. The article summarizes recent advances in both fields of study and presents perspectives for further development and possible applications.

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3 Acta Biochimica Polonica

1 2011

1 2006

1 2005

1 Bordbar A.-K.

1 Burda K.

1 Chmiel D.

1 Dazhampanah H.

1 Dubin A.

1 Dubin G.

1 Fornal M.

1 Grodzicki T.

1 Kaczmarska M.

1 Kopyściańska Z.

1 Korecki J.

1 Mak P.

1 Matlak K.

1 Maziarka K.

1 Mousavi S. H.-A.

1 Rzychon M.

1 Stec-Niemczyk J.

1 Wladyka B.

Search results

Analysis of oxygen binding by hemoglobin on the basis of mean intrinsic thermodynamic quantities

Effects of low doses of gamma rays on the stability of normal and diabetic erythrocytes

New generation of peptide antibiotics