Peroxynitrite rapidly permeates phospholipid membranes

摘要

Peroxynitrite (ONOO~-) is a potent oxidant implicated in a number of pathophysiological processes. The activity of ONOO~- is related to its accessibility to biological targets before its spontaneous decomposition (t_1/2 ≈ 1 s at pH 7.4, 37 deg C). Using model phospholipid vesicular systems and manganese porphyrins as reporter molecules, we demon- strated that ONOO~- freely crosses phospholipid membranes. The calculated permeability coefficient for ONOO~- is ≈8.0 * 10~-4 cm.s~-1, which compares well with that of water and is ≈400 times greater than that of superoxide. We suggest that ONOO~- is a significant biological effector molecule not only because of its reactivity but also because of its high diffus- ibility.