Student Number : 0002483R - MSc dissertation - School of Molecular and Cell Biology - Faculty of Science / Isothermal titration calorimetry was used to investigate the forces that drive ligand binding to the active site of rGST M1-1. In an attempt to gain insight into the recognition of non-substrate ligands by GSTs, this study also investigates interactions between rGST M1-1 and ANS, a non-substrate ligand. At 25 °C, complex formation between rGST M1-1 and GSH, GSO3 -, and S-hexylglutathione is characterised by a monophasic binding isotherm with Kd values of 38.5 mM, 2.1 mM and 0.2 mM, respectively. One molecule of each ligand is bound per monomer of rGST M1-1. Binding of these ligands is enthalpically favourable and entropically unfavourable with a resultant favourable Gibbs free energy, overall. The effects of temperature and buffer ionisation on the energetics of binding were studied. The enthalpic and entropic contributions for all three ligands exhibited temperature dependence over the temperature range investigated (5-30 °C). The Gibbs free energy showed negligible changes with increasing temperature due to enthalpy-entropy compensation. The temperature dependence of the binding enthalpy yielded heat capacity changes of – 2.69 kJ/mol/K and –3.68 kJ/mol/K at 25 °C for GSH and S-hexylglutathione binding and –1.86 kJ/mol/K overall for GSO3 -. The linear dependence of DH on temperature for GSO3 - binding to rGST M1-1 suggests the formation of a more constrained complex which limits the fluctuations in conformations of the mu-loop at the active site. The non-linear dependence of DH on temperature for GSH and Shexylglutathione binding to the enzyme suggests the formation of a complex that samples different bound conformations due to the mobility of the mu-loop even after ligand is bound. Calorimetric binding experiments in various buffer systems with different ionisation enthalpies suggest that the binding of GSH to rGST M1-1 is coupled to the deprotonation of the thiol of GSH while GSO3 - binding to rGST M1-1 is independent of the buffer ionisation. At 25 °C, the rGST M1-1#1;ANS association is represented by a monophasic binding isotherm with one molecule of ANS bound per monomer of rGST M1-1. The interaction is both enthalpically and entropically driven with a Kd value of 27.2 mM representing moderate affinity. The effect of temperature on the interaction was investigated over the temperature range of 5-30 °C. The linear dependence of the binding enthalpy on temperature indicates that no significant structural changes occur upon binding of ANS to the enzyme (DCp = -0.34 kJ/mol/K). The change in heat capacity associated with the interaction can be attributed to the burial of the polar sulphonate group of ANS and the exposure of the anilino and naphthyl rings to solvent as well as the possibility of weak electrostatic interactions between ANS and residues at the active site. The effect of ethacrynic acid, GSH, GSO3 - and S-hexylglutathione on the fluorescence of ANS was investigated in order to obtain some idea as to the location of the ANS binding site on rGST M1-1. ANS was displaced by GSO3 -, S-hexylglutathione and ethacrynic acid, while no displacement occurred upon binding of GSH to the active site of rGST M1-1. Displacement studies and molecular docking simulations indicate that ANS binds to the H-site of rGST M1-1 and the possibility of a second binding site for the molecule cannot be ruled out.

This diploma thesis deals with small air-conditioning units for ventilation of flats and family houses. First, I studied two compact air-conditioning units, processed measured data, comparing and evaluating a unit with better technical characteristics. The second task is to process variants of design solutions for the ventilation of a family house. The first variant calculates with only one air-conditioning unit when ventilating, in the second variant two air-handling units are designed. These variants were then compared and evaluated in terms of acquisition cost and operating costs.

This master thesis is solving measuring the efficiency heat recovery and application unit, which includes heat recovery into selected building. In the first part of the thesis are analy-zed the different types of heat recovery system, their behavior and suitability of use in HVAC systems. The second part includes the actual experiment, when were measured parameters of air, which passed through the unit and then were analyzed the results. In the last part, third, was measured unit applied to the selected house and was compared to operation of the unit in case of use by the producer given unit parameters and measured parameters.