Reduction of ascorbate free radical by the plasma membrane of synaptic terminals from rat brain
- Citation:
- Reduction of ascorbate free radical by the plasma membrane of synaptic terminals from rat brain, Samhan-Arias, A. K., Duarte R. O., Martin-Romero F. J., Moura J. J., and Gutierrez-Merino C. , Arch Biochem Biophys, Jan 15, Volume 469, Number 2, p.243-54, (2008)
Abstract:
Synaptic plasma membranes (SPMV) decrease the steady state ascorbate free radical (AFR) concentration of 1mM ascorbate in phosphate/EDTA buffer (pH 7), due to AFR recycling by redox coupling between ascorbate and the ubiquinone content of these membranes. In the presence of NADH, but not NADPH, SPMV catalyse a rapid recycling of AFR which further lower the AFR concentration below 0.05 microM. These results correlate with the nearly 10-fold higher NADH oxidase over NADPH oxidase activity of SPMV. SPMV has NADH-dependent coenzyme Q reductase activity. In the presence of ascorbate the stimulation of the NADH oxidase activity of SPMV by coenzyme Q(1) and cytochrome c can be accounted for by the increase of the AFR concentration generated by the redox pairs ascorbate/coenzyme Q(1) and ascorbate/cytochrome c. The NADH:AFR reductase activity makes a major contribution to the NADH oxidase activity of SPMV and decreases the steady-state AFR concentration well below the micromolar concentration range.
Notes:
1096-0384 (Electronic)0003-9861 (Linking)Journal ArticleResearch Support, Non-U.S. Gov't
