INVESTIGADORES
DUPUY Fernando Gabriel
congresos y reuniones científicas
Título:
Membrane influence on acetylcholinesterase inhibition by epigallocatechin-3-O-gallate (EGCG)
Autor/es:
SALAZAR, PAULA BELÉN; DUPUY, FERNANDO G.; RODRÍGUEZ VAQUERO, MJ; MINAHK, CARLOS J.
Reunión:
Congreso; 64th Annual Meeting of the Biophysical Society; 2020
Institución organizadora:
Biophysical Society
Resumen:
The aim of the present work was to study the inhibition of the erythrocyte acetylcholinesterase (AChE) by EGCG. Here we show that EGCG preferentially acts on the membrane-bound enzyme rather than on the soluble form. Actually, it may bind to the membrane surface, which might improve the interaction between EGCG and AChE. The binding of EGCG to the ghost membrane was studied by measuring the steady-state DPH fluorescence anisotropy and analyzing the quenching of R18 fluorescence.As other membrane-bound enzymes, whose activities depend on membrane lipid composition and order, AChE has been previously shown to depend on phospholipid fatty acids composition and now we proved that low cholesterol levels deepen the enzyme inhibition by EGCG. Besides, an enhanced quenching of rhodamine R18 fluorescence by EGCG, was observed when cholesterol content of membranes was reduced, leading us to hypothesize that EGCG might interact with interfacial portion of membranes. On the other hand, a more precise localization of EGCG in membranes when cholesterol was changed was assessed by IR spectroscopy. The CH2 symmetric stretching vibration significantly down-shifted in ghosts treated with MβCD, indicating that a higher degree of acyl chain packaging is induced by the presence of EGCG. This change is in the same order of magnitude than the changes observed in control ghosts in the absence of EGCG, when temperature was raised from 15 to 45 °C. Surprisingly, only minor changes on the hydration level of the interfacial region of membranes was observed. It can be proposed that hydroxyl groups from the catechin may replace water molecules as hydrogen donors.It can be concluded that interactions between EGCG and membrane lipid components are noteworthy since they can determine the degree of inhibition of membrane bound enzymes by this polyphenol.