Inhibition of Cholinesterase by Dialkylcarbamates
Abstract The pI50 index and separation coefficients of chosen 3-N,N-diethylaminophenyl-N′,N′-dialkylcarbamates were determined. Index pI50 (pI50 = negative logarithm of molar concentration of inhibitor inhibiting the enzyme activity by 50%) describes the effectiveness of the inhibitor. The rate of ability of the inhibitor to pass the blood-brain barrier is usually described by the separation coefficient in a system n-octanol/water (Kow). Obtained results were compared with pI50 and Kow of Exelon®, the commercially used drug against the Alzheimer’s disease.
Kinetics of the total hydrolysis of acetyl-β-methylcholine by acetylcholinesterase
Mechanism and kinetics of in vitro hydrolysis of acetyl-β-methylcholine by acetylcholinesterase from electric eel in a mixed batch reactor at 25 and 37°C, pH 8, ionic strength 0.11 M and catalytic activity of the enzyme preparat of 3.5 U mL−1 were studied. The optimal kinetic parameters were determined.
The peculiar thermo-structural behavior of the anionic lipid DMPG.
Aqueous dispersions of the anionic phospholipid dimyristoyl phosphatidylglycerol (DMPG), around 100 mM ionic strength, are known to exhibit a thermal behavior similar to that of the largely studied lipid dimyristoyl phosphatidylcholine (DMPC), which undergoes a gel to liquid crystalline phase transition at 23 degrees C, well characterized by differential scanning calorimetry (DSC), and other methods. However, at low ionic strength, DMPG has been shown to present a large gel-fluid transition region, ranging from 18 to 35 degrees C. This intermediate phase is optically transparent and characterized by a continuous change in membrane packing. Structural properties of the DMPG gel-fluid transition region will be discussed, based on results obtained by several techniques: electron spin resonance (ESR) of spin labels at the membrane surface and intercalated at different depths in the bilayer; light scattering; DSC; small angle X-ray scattering (SAXS); and fluorescence spectroscopy of probes in the bilayer.