<title>Enzyme molecule control of the substrate microflows and some problems of optical diagnostics</title>

Abstract

We studied the enzyme acetylcholinesterase (AChE) that catalyses the hydrolysis of acetylcholine (ACh) -- cell neuromediator. After transfer of excitation ACh must be removed from the synaptic cleft in hundreds of microseconds. This is accomplished by removing of acetate (A) and choline (Ch) that are the products of 'cutting' of ACh by AChE. High activity of the enzyme is related with the large dipole moment of AChE that attracts positively charged molecules of ACh into active site (AS) and also with the fast removing of the reaction products from AS. One of the hypothesis accounting for the fast removing of A and Ch from the AS pocket presumes the existence of a 'back door' that allows them to leave the pocket without interference with the molecules of ACh that penetrate inside the AS. We made an attempt of verification of the 'back door' hypothesis by means of computational experiment for 2D and 3D spaces. We considered the problem of penetration of ACh and exit of the negatively charged A and positively charged Ch under the conditions of fluctuating potential relief of the AChE AS. For the laser spectroscopy we pose two problems: (a) determination of the dipole moment of AChE in the case this molecule is surrounded by ACh molecules by means of the electro-optical method and (b) detection of AS conformations related with functioning of the 'back door' (the ring-system of Trp84). We report on Raman spectroscopy study of the influence of crown-esters on amino groups.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.