CURRENT FLUCTUATIONS OF BILAYER-LIPID MEMBRANES MODIFIED BY GLUCOSE-OXIDASE

The study of current fluctuations of metal-supported bilayer lipid mem branes (s-BLM) modified by glucose oxidase (GOX) is presented. Current fluctuations are expressed as a dependence of spectral density (P) on a frequency and as a dependence of P at certain frequency (10, 100 an d 1000 Hz) on the concentration of glucose and/or current flowing acro ss a membrane. We have shown that in the frequency range of 10-1000 Hz , the dependence of spectral density on the frequency of fluctuations can be described by the dependence 1/f(alpha), where alpha similar to 1. This dependence is typical for fluctuations of the current flowing across free-standing BLM observed earlier. The amplitude of P for s-BL M with immobilized GOX was considerably larger than that without GOX. However, the current flowing across s-BLM was higher than that for s-B LM with immobilized GOX. The origin of fluctuations is explained by me ans of the peculiarities of s-BLM structure and by the influence of co nformational changes of GOX on the properties of supported bilayers. ( C) 1998 Elsevier Science S.A, All rights reserved.