Effects of High Pressure on Glucose Transport in the Human Erythrocyte

The effects of raised hydraulic pressure on D-glucose exit from human red cells at 25 degrees C were determined using light scattering measurements in a sealed pressurized spectrofluorimeter cuvette. The reduction in the rates of glucose exit with raised pressure provides an index of the activation volume, deltaV++ (delta ln k/deltaP)(T) = -deltaV++/RT. Raised pressure decreased the rate constant of glucose exit from 0.077 +/- 0.003 s(-1) to 0.050 +/- 0.002 s(-1) (n = 5, P < 0.003). The Ki for glucose binding to the external site was 2.7 +/- 0.4 mm (0.1 MPa) and was reduced to 1.45 +/- 0.15 mm (40 MPa), (P < 0.01, Student's t test). Maltose had a biphasic effect on deltaV++. At [maltose] <250 microM, deltaV++ of glucose exit increased above that with [maltose = 0 mM], at >1 mm maltose, deltaV++ was reduced below that with [maltose = 0 mM]. Pentobarbital (2 mM) decreased the deltaV++ of net glucose exit into glucose-free solution from 30 +/- 5 ml mol(-1) (control) to 2 +/- 0.5 ml mol(-1) (P < 0.01). Raised pressure had a negligible effect on L-sorbose exit. These findings suggest that stable hydrated and liganded forms of GLUT with lower affinity towards glucose permit higher glucose mobilities across the transporter and are modelled equally well with one-alternating or a two-fixed-site kinetic models.     

Effect of hydrostatic pressure on unfolding of alpha-lactalbumin: volumetric equivalence of the molten globule and unfolded state

The effect of pressure on the unfolding of bovine alpha-lactalbumin was investigated by ultraviolet absorption methods. The change of molar volume associated with unfolding, deltaV, was measured in the presence or absence of guanidine hydrochloride at pH 7. The deltaV was estimated to be -63 cm3/mol in the absence of a chemical denaturant. While in the presence of guanidine hydrochloride (GuHCl), it was found that deltaV was -66 cm3/mol at 25 degrees C and was independent of the concentration of GuHCl, despite the fact that the molten globule fraction in the total unfolding product decreased with the increase of GuHCl concentration. The results indicate that the volume of alpha-lactalbumin only changes at the transition from a native to a molten globule state, and almost no volume change has been found during the transition from a molten globule to the unfolded state.     

High pressure nmr study of dihydrofolate reductase from a deep-sea bacterium Moritella profunda.

We have investigated the effect of pressure and temperature on the structural and thermodynamic stability of a protein dihydrofolate reductase from a deep-sea bacterium Moritella profunda in its folate-bound form in the pressure range between 3 and 375 MPa and the temperature range between -5 and 30 degrees C. The on-line cell variable pressure 1H NMR spectroscopy has been used to analyze the chemical shift and signal intensity in one-dimensional 1H NMR spectra. Thermodynamic analysis based on signal intensities from protons in the core part indicates that the thermodynamic stability of Moritella profunda DHFR is relatively low over the temperature range between -5 and 30 degrees C (deltaG0=15.8 +/- 4.1 kJ/mol at 15 degrees C), but is well adapted to the living environment of the bacterium (2 degrees C and 28 MPa), with the maximum stability around 5 degrees C (at 0.1 MPa) and a relatively small volume change upon unfolding (deltaV= 66 +/- 19 ml/mol). Despite the relatively low overall stability, the conformation in the core part of the folded protein remains intact up to approximately 200 MPa, showing marked stability of the core of this protein.     

Selective neoglycosylation increases the structural stability of vicilin, the 7S storage globulin from pea seeds

The effects of glycosylation on the stability and subunit interactions of vicilin, the major storage protein in pea seeds, were investigated. Glycosylated vicilin derivatives were prepared by alkylation of lysine epsilon-amino groups with various carbohydrates. Average modification levels of 13.4 +/- 3.0, 11.1 +/- 3.6, 7.5 +/- 4.2, and 4.7 +/- 0.3 moles of carbohydrate/mol of vicilin were obtained with glucose, galactose, galacturonic acid, and lactose, respectively. Nondenaturing polyacrylamide gel electrophoresis and size-exclusion chromatography indicated that the quaternary structure and hydrodynamic radius of vicilin were not affected by glycosylation at the levels used. We have previously shown that application of hydrostatic pressure causes dissociation of vicilin subunits [C. Pedrosa and S. T. Ferreira (1994) Biochemistry 33, 4046-4055]. Analysis of pressure dissociation data allowed determination of the Gibbs free energy change (deltaG(diss)) and molar volume change (deltaV(diss)) of dissociation of vicilin subunits. For unmodified vicilin, deltaG(diss) = 18.2 kcal/mol and deltaV(diss) = -102 ml/mol. Glycosylated vicilin derivatives were significantly stabilized against subunit dissociation, with deltaG(diss) of 19.4, 19.2, 20.6, and 22.1 kcal/mol for glucose, galactose, lactose, and galacturonic acid derivatives, respectively. No changes in deltaV(diss) were found for the glucose and galactose derivatives, whereas deltaV(diss) of -128 and -135 ml/mol, respectively, were found for the lactose and galacturonic acid derivatives. The glycosylated derivatives also appeared more resistant to unfolding by guanidine hydrochloride than unmodified vicilin. Intrinsic fluorescence lifetime measurements showed that glycosylation caused a significant increase in heterogeneity of the fluorescence decay, possibly reflecting increased conformational heterogeneity of glycosylated derivatives relative to unmodified vicilin. These results indicate that the stability and subunit interactions of vicilin may be modulated by mild, selective glycosylation at low modification levels, an effect that may be of interest in the study of other oligomeric proteins.     

Initiation of Bacillus spore germination by hydrostatic pressure: effect of temperature.

Suspensions of Bacillus cereus T, B. subtilis, and B. pumilus spores in water or potassium phosphate buffer were germinated by hydrostatic pressures of between 325 and 975 atm. Kinetics of germination at temperatures within the range of 25 to 44 degrees C were determined, and thermodynamic parameters were calculated. The optimum temperature for germination was dependent on pressure, species, suspending medium, and storage time after heat activation. Germination rates increased significantly with small increments of pressure, as indicated by high negative deltaV values of -230 +/- 5 cm3/mol for buffered B. subtilis (500 to 700 atm) and B. pumilus (500 atm) spores and -254 +/- 18 cm3/mol for aqueous B. subtilis (400 to 550 atm) spores at 40 degrees C and -612 +/- 41 cm3/mol for B. cereus (500 to 700 atm) spores at 25 degrees C. The ranges of thermodynamic constants calculated at 40 degrees C for buffered B. pumilus and B. subtilis spores at 500 and 600 atm and for aqueous B. subtilis spores at 500 atm were: Ea = 181,000 to 267,000 J/mol; deltaH = 178,000 to 264,000 J/mol; deltaG = 94,000 to 98,300 J/mol; deltaS = 264 to 544 J/mol per degree K. These values are consistent with the concept that the transformation of a dormant to a germinating spore induced by hydrostatic pressure involves either hydration or a reduction in the visocosity of the spore core and a conformational change of an enzyme.     

High-performance liquid chromatographic enantioseparation of Betti base analogs on a newly developed isopropyl carbamate-cyclofructan6-based chiral stationary phase

The direct separation of the enantiomers of 1-(α-aminoarylmethyl)-2-naphthol, 1-(α-aminoalkyl)-2-naphthol, 2-(α-aminoarylmethyl)-1-naphthol analogs, and 2-(1-amino-2-methylpropyl)-1-naphthol) was performed on a newly developed chiral stationary phase containing isopropyl carbamate-cyclofructan6 as chiral selector, with n-heptane/alcohol/trifluoroacetic acid as mobile phase. The effects of the mobile-phase composition, the nature and concentration of the alcoholic and acidic modifiers, and the structures of the analytes on the retention and resolution were investigated. In some cases, separations were carried out at constant mobile-phase compositions in the temperature range 5-40°C. Thermodynamic parameters and T(iso) values were calculated from plots of ln k' or ln α versus 1/T. -Δ(ΔH°) ranged from 2.8 to 3.2 kJ mol(-1) , -Δ(ΔS°) from 7.7 to 10.1 J mol(-1) K(-1) , and -Δ(ΔG°) from 0.2 to 0.5 kJ mol(-1) . It was found that the enantioseparations were enthalpy driven. The sequence of elution of the stereoisomers determined in some cases was (R) < (S).     

Kinetically robust monomeric protein from a hyperthermophile

Equilibrium and kinetic studies were carried out under denaturation conditions to clarify the energetic features of the high stability of a monomeric protein, ribonuclease HII, from a hyperthermophile, Thermococcus kodakaraensis (Tk-RNase HII). Guanidine hydrochloride (GdnHCl)-induced unfolding and refolding were measured with circular dichroism at 220 nm, and heat-induced denaturation was studied with differential scanning calorimetry. Both GdnHCl- and heat-induced denaturation are very reversible. It was difficult to obtain the equilibrated unfolding curve of Tk-RNase HII below 40 degrees C, because of the remarkably slow unfolding. The two-state unfolding and refolding reactions attained equilibrium at 50 degrees C after 2 weeks. The Gibbs energy change of GdnHCl-induced unfolding (DeltaG(H(2)O)) at 50 degrees C was 43.6 kJ mol(-1). The denaturation temperature in the DSC measurement shifted as a function of the scan rate; the denaturation temperature at a scan rate of 90 degrees C h(-1) was higher than at a scan rate of 5 degrees C h(-1). The unfolding and refolding kinetics of Tk-RNase HII were approximated as a first-order reaction. The ln k(u) and ln k(r) values depended linearly on the denaturant concentration between 10 and 50 degrees C. The DeltaG(H(2)O) value obtained from the rate constant in water using the two-state model at 50 degrees C, 44.5 kJ mol(-1), was coincident with that from the equilibrium study, 43.6 kJ mol(-1), suggesting the two-state folding of Tk-RNase HII. The values for the rate constant in water of the unfolding for Tk-RNase HII were much smaller than those of E. coli RNase HI and Thermus thermophilus RNase HI, which has a denaturation temperature similar to that of Tk-RNase HII. In contrast, little difference was observed in the refolding rates among these proteins. These results indicate that the stabilization mechanism of monomeric protein from a hyperthermophile, Tk-RNase HII, with reversible two-state folding is characterized by remarkably slow unfolding.     

Inactivation of animal viruses during sewage sludge treatment.

Using a previously developed filter adsorption technique, the inactivation of a human rotavirus, a coxsackievirus B5, and a bovine parvovirus was monitored during sludge treatment processes. During conventional anaerobic mesophilic digestion at 35 to 36 degrees C, only minor inactivation of all three viruses occurred. The k' values measured were 0.314 log10 unit/day for rotavirus, 0.475 log10 unit/day for coxsackievirus B5, and 0.944 log10 unit/day for parvovirus. However, anaerobic thermophilic digestion at 54 to 56 degrees C led to rapid inactivation of rotavirus (k' greater than 8.5 log10 units/h) and of coxsackievirus B5 (k' greater than 0.93 log10 unit/min). Similarly, aerobic thermophilic fermentation at 60 to 61 degrees C rapidly inactivated rotavirus (k' = 0.75 log10 unit/min) and coxsackievirus B5 (k' greater than 1.67 log10 units/min). Infectivity of parvovirus, however, was only reduced by 0.213 log10 unit/h during anaerobic thermophilic digestion and by 0.353 log10 unit/h during aerobic thermophilic fermentation. Furthermore, pasteurization at 70 degrees C for 30 min inactivated the parvovirus by 0.72 log10 unit/30 min. In all experiments the contribution of temperature to the total inactivation was determined separately and was found to be predominant at process temperatures above 54 degrees C. In conclusion, the most favorable treatment to render sludge hygienically safe from the virological point of view would be a thermal treatment (60 degrees C) to inactivate thermolabile viruses, followed by an anaerobic mesophilic digestion to eliminate thermostable viruses that are more sensitive to chemical and microbial inactivations.     

Inactivation of animal viruses during sewage sludge treatment

Using a previously developed filter adsorption technique, the inactivation of a human rotavirus, a coxsackievirus B5, and a bovine parvovirus was monitored during sludge treatment processes. During conventional anaerobic mesophilic digestion at 35 to 36 degrees C, only minor inactivation of all three viruses occurred. The k' values measured were 0.314 log10 unit/day for rotavirus, 0.475 log10 unit/day for coxsackievirus B5, and 0.944 log10 unit/day for parvovirus. However, anaerobic thermophilic digestion at 54 to 56 degrees C led to rapid inactivation of rotavirus (k' greater than 8.5 log10 units/h) and of coxsackievirus B5 (k' greater than 0.93 log10 unit/min). Similarly, aerobic thermophilic fermentation at 60 to 61 degrees C rapidly inactivated rotavirus (k' = 0.75 log10 unit/min) and coxsackievirus B5 (k' greater than 1.67 log10 units/min). Infectivity of parvovirus, however, was only reduced by 0.213 log10 unit/h during anaerobic thermophilic digestion and by 0.353 log10 unit/h during aerobic thermophilic fermentation. Furthermore, pasteurization at 70 degrees C for 30 min inactivated the parvovirus by 0.72 log10 unit/30 min. In all experiments the contribution of temperature to the total inactivation was determined separately and was found to be predominant at process temperatures above 54 degrees C. In conclusion, the most favorable treatment to render sludge hygienically safe from the virological point of view would be a thermal treatment (60 degrees C) to inactivate thermolabile viruses, followed by an anaerobic mesophilic digestion to eliminate thermostable viruses that are more sensitive to chemical and microbial inactivations.     

Osmotic pressure measurements on insulin: anomalous results indicate that the monomer is preferentially adsorbed

The concentration dependence of the number average molecular weight of insulin at pH 2, ionic strength 0.05, and 20 degrees C as determined by osmotic pressure measurements indicates that the hormone is a homogeneous protein of molecular weight close to that of the dimer. Since sedimentation equilibrium experiments confirm what is well known, namely that insulin is a self-associating protein dissociating to monomer under these conditions, an explanation for the anomaly was sought in the possible loss of protein from solution by adsorption. Analysis of the results strongly supports this conclusion and consideration of the adsorption properties of insulin in terms of hydrophobic interactions shows them to be consistent with the behaviour of insulin as a self-associating protein. The monomer appears to be the primary molecular species responsible for insulin adsorption.     

Reactive uptake governs the pulmonary air space removal of inhaled nitrogen dioxide

With the use of an isolated rat lung model, we investigated pulmonary air space absorption kinetics of the reactive gas NO2 in an effort to determine the contributory role of chemical reaction(s) vs. physical solubility. Unperfused lungs were employed, because vascular perfusion had no effect on acute (0- to 60-min) NO2 absorption rates. We additionally found the following: 1) Uptake was proportional to exposure rates (2-14 micrograms NO2/min; 10-63 ppm; 37 degrees C) but saturated with exposures greater than or equal to 14 micrograms NO2/min. 2) Uptake was temperature (22-48 degrees C) dependent but, regardless of temperature, attained apparent saturation at 10.6 micrograms NO2/min. 3) Lung surface area (SA) was altered by increasing functional residual capacity (FRC). Expanded SA (8 ml FRC) and temperature (48 degrees C) both raised fractional uptakes (greater than or equal to 0.81) relative to 4 ml FRC, 37 degrees C (0.67). Uptake rates normalized per unit estimated SA revealed no independent effect of FRC on fractional uptake. However, temperature produced a profound effect (48 degrees C = 0.93; 4 and 8 ml FRC = 0.54). 4) Arrhenius plots (ln k' vs. 1/T), which utilized derived reactive uptake coefficients (k'), showed linearity (r2 = 0.94) and yielded an activation energy of 7,536 kcal.g-1.mol-1 and Q10 of 1.43, all consistent with a reaction-mediated process. These findings, particularly the effects of temperature, suggest that acute NO2 uptake in pulmonary air spaces is, in part, rate limited by chemical reaction of NO2 with epithelial surface constituents rather than by direct physical solubility.     

Development and characterization of an immunoaffinity column for the selective extraction of bisphenol A from serum samples

An immunoaffinity column (IAC) was developed by covalently coupling polyclonal antibodies against estrogenic bisphenols to CNBr-activated Sepharose 4B. The IAC showed high affinity for bisphenol A, while phenol was barely retained. Proteins in the sample matrix showed little nonspecific adsorption on the column. The best binding solvent for bisphenol A was found to be 0.01 mol l(-1) phosphate-buffered saline (PBS) and the optimal operating temperature was 4 degrees C. The bound bisphenol A could be quantitatively recovered by 1 ml of methanol-water (80:20) with an average recovery of 91.8% and a relative standard deviation of 7.1% (n=6). The immunoaffinity column has been successfully used for the isolation and purification of bisphenol A from serum samples.     

Liquid chromatographic separation of darunavir enantiomers on coated and immobilized amylose tris(3, 5-dimethylphenylcarbamate) chiral stationary phases

Liquid chromatographic separation of darunavir enantiomers on covalently bonded and physically adsorbed polysaccharide chiral stationary phases was studied at different temperatures. The separations were accomplished under normal-phase conditions by using different combinations of hexane, organic modifiers (2-propanol, 1-propanol and ethanol), and diethylamine as mobile phase solvents. The effect of organic modifiers and the column temperature on retention, separation, and resolution was investigated. The observed differences were explained in terms of the coated and immobilized nature of the two columns. Van't Hoff plots (ln k' vs. 1/T, ln α vs. 1/T) and apparent thermodynamic parameters were derived to understand the effect of temperature on separation.     

Thermodynamics of the conversion of aqueous xylose to xylulose

The thermodynamics of the conversion of aqueous xylose to xylulose has been investigated using high-pressure liquid chromatography (HPLC) and microcalorimetry. The reaction was carried out in aqueous phosphate buffer over the pH range 6.8-7.4 using solubilized glucose isomerase with MgSO(4) as a cofactor. The temperature range over which this reaction was investigated was 298.15-342.15 K. A combined analysis of both the HPLC and microcalorimetric data leads to the following results at 298.15 K for the conversion process: DeltaG degrees = 4389 +/- 31 J mol(-1), DeltaH degrees = 16090 +/- 670 J mol(-1), and DeltaC(p) degrees = 40 +/- 23 J mol(-1) K(-1). The temperature dependence of the equilibrium constant for the reaction is expressed as R ln K = -4389/298.15 +16090[(1/298.15)-(1/T)]+40[(298.15/T)-1 + ln(T/298.15)]. Comparisons are made with literature data.     

Exploration of pressure-induced dissociation of pyruvate oxidase.

The dissociation of pyruvate oxidase (PO) caused by pressure up to 220 MPa at various conditions was explored by measuring the intrinsic fluorescence spectra and polarization. At 5 degrees C and pH 7.6 the standard volume change (deltaV0) and free energy upon dissociation of the enzyme is -220 ml/mol and 29.83 kCal/mol, respectively. It was found that FAD was irreversibly removed during the pressure-dissociation of the enzyme. A much smaller standard volume change (-153 ml/mol) and lower free energy (24.92 kCal/mol) of apo-pyruvate oxidase (apo-PO) compared with the native enzyme indicated that FAD played very important role in stabilizing the enzyme and significantly influenced the standard volume change. The substrate pyruvic acid can significantly stabilize the enzyme against pressure in spite the standard volume for the enzyme in this case has a big increase relative to the native enzyme. The comparison of the intrinsic fluorescence of the native and the activated enzyme obtained by limited proteolysis indicated that the physical separation of alpha-peptide from the enzyme only occurred when the subunits were dissociated from each other under pressure.     

Water-phase palmitate concentrations in equilibrium with albumin-bound palmitate in a biological system.

The palmitate (PA) binding and transport capacity of human and bovine red cell membranes enables us to establish, in a biological system, the existence of a well-defined monomer concentration in equilibrium with PA bound to bovine serum albumin (BSA, 30 microM) inside the resealed red cell ghosts. Supernatants of suspensions of the [3H]PA-labeled ghosts contain a tiny quantity of dissolved binding capacities besides the monomer PA. This is demonstrated by linear regression of supernatant tracer concentrations versus ghost concentrations in a dilution series. The extrapolated value, corresponding to zero ghost concentration, is the monomer PA concentration in equilibrium with PA bound to BSA within the ghosts in molar ratio (nu). Measurements have been carried out for nu between 0.1 and 1.5 and at 0 degrees C, 10 degrees C, 23 degrees C and 38 degrees C. The important nu-dependent binding of PA to the ghost membrane itself enables us to use preparations of BSA-free ghosts in the same way, whereas this is impossible in the case of arachidonic acid. Within the physiological range of nu the PA monomer concentrations are accounted for by an apparent dissociation equilibrium constant (Kd) 3.4 10(-8) M at 38 degrees C calculated on basis of three equivalent binding sites per mol BSA. Kd depends on temperature with a well-defined enthalpy of 38.4 kJ/mol.     

A reversed-phase ion-pair high-performance liquid chromatography method for bovine testicular hyaluronidase digests using postcolumn derivatization with 2-cyanoacetamide and ultraviolet detection

A reversed-phase ion-pair HPLC method for separating hyaluronic acid oligomers, using a polymeric C18 column at alkaline pH, is described. As the concentration of the ion-pairing agent tetrabutylammonium hydroxide increased, over the range of 0.01 to 0.06M, the capacity factors (k') of tetra- to dodecasaccharide decreased. The change in k', for each increment in pairing agent, increased with oligomer molecular weight. When changing mobile phase pH from 7 to 8, k' dramatically decreased and remained unchanged from pH 8 to 11. The isocratic separation was optimized to resolve tetrato dodecasaccharide at pH 9.0 in under 19 min. The postcolumn derivatizing agent 2-cyanoacetamide reacted with the reducing N-acetylglucosamine end groups of hyaluronic acid oligomers to yield reaction products that were monitored at 27 nm. In a series of control experiments using decasaccharide and N-acetylglucosamine, it was found that maximum product formation took place at pH 9 and was greatly influenced by borate buffer concentration. The optimum concentration for 2-cyanoacetamide was 0.33% and a temperature of 100 degrees C gave the best signal to noise ratio for the postcolumn reaction. The method is linear and reproducible, and has a lower limit of detection for tetrasaccharide of 20 ng (25 pmol). This system is suitable for studying the degradation kinetics of purified hyaluronic acid oligomers by bovine testicular hyaluronidase. Extension of the method to fluorescent and electrochemical detection and its applicability to other glycosaminoglycans is discussed.     

Thermodynamics of phospholipid bilayer assembly

Thermodynamic properties of bilayer assembly have been obtained from measurements of the solubility of the sodium salt of dimyristoylphosphatidylglycerol (DMPG) in water. The standard free energy of bilayer assembly delta G degree a is shown to be RT 1n Xs + zF psi 0 where Xs is the mole fraction of dissolved lipid, F is the Faraday constant, z is the valence of the counterion (Na+), and psi 0 is the electrical double-layer potential of the ionized bilayer. The function d 1n Xs/dT was found to be discontinuous at 24 degrees C, the gel-liquid-crystal transition temperature (Tm) for DMPG. This function was unaffected when solubilities were measured in 0.001 M NaCl solutions; thus, psi 0 is constant in the experimental temperature interval (4-40 degrees C). Using a value of psi 0 = -180 mV [Eisenberg et al. (1979) Biochemistry 18, 5213-5223], and the temperature dependence of delta G degrees a, values for delta H degrees a and delta S degree a at 24 degrees C were calculated for the gel and liquid-crystal states of DMPG. For the gel, delta H degrees a and T delta S a are -26.2 and 12.7 kcal/mol, respectively; for the liquid-crystal, delta H degrees a and T delta S degrees a are -19.2 and -5.7 kcal/mol, respectively. The calculated value for the latent heat of the gel-liquid-crystal transition is 7 kcal/mol, in agreement with calorimetric measurements.     

颗粒状固定化青霉素酰化酶的研究

将巨大芽孢杆菌 (Bacillusmegaterium)胞外青霉素酰化酶通过共价键结合到聚合物载体EupergitC颗粒环氧基团上 ,制成的颗粒状固定化青霉素酰化酶表现活力达 1 40 0 μ/g左右。固定化酶水解青霉素的最适 pH8 0 ,最适温度为 55℃。在pH6 0～ 8 5、温度低于 40℃时固定化酶活力稳定。在 pH8 0、温度 37℃时 ,固定化酶对青霉素的表现米氏常数Ka为 2×1 0 - 2 mol/L ;苯乙酸为竞争性抑制剂 ,抑制常数Kip为 2 8× 1 0 - 2 mol/L ;6 APA为非竞争性抑制剂 ,抑制常数Kia为 0 1 2 5mol/L。固定化酶水解青霉素 ,投料浓度为 8% ,在使用 2 0 0批后 ,保留活力 80 %左右 ,6 APA收率平均达 89 48%。     

Dielectric spectroscopy on aqueous electrolytic solutions

In this work, detailed dielectric measurements are presented on aqueous electrolytic solutions of NaCl and KCl in a broad frequency range, typical for modern telecommunication techniques. The complex dielectric permittivity or equivalently the complex conductivity are systematically studied as function of frequency (100 MHz-40 GHz), temperature (10-60 degrees C) and molar concentration (0.001-1 mol/l). By a detailed analysis of the dielectric results using an asymmetrically broadened Cole-Davidson distribution of relaxation times, in addition to dc conductivity, the dielectric response as function of frequency, temperature, and molar concentration was fully parameterized by a total of 13 parameters. This model ansatz and the 13 parameters include an enormous predictive power, allowing a reasonable estimation of the dielectric constant, loss, and the conductivity for any set of external variables frequency, temperature and concentration. The proposed method is not only useful for rather simple electrolytic solutions, but also for cell suspensions and biological matter, if additional processes, especially at low frequencies, are adequately taken into account.