solubility and permeation of hydrogen sulfide in lipid membranes溶解度和硫化氢在脂质膜的渗透.pdf

Solubility and Permeation of Hydrogen Sulfide in Lipid Membranes 1,2 2,3 1,2 ´ ¨ 2,3 Ernesto Cuevasanta , Ana Denicola , Beatriz Alvarez *, Matıas N. Moller * ´ ´ 1 Laboratorio de Enzimologıa, Facultad de Ciencias, Universidad de la Republica, Montevideo, Uruguay, 2 Center for Free Radical and Biomedical Research, Universidad de ´ ´ ´ ´ la Republica, Montevideo, Uruguay, 3 Laboratorio de Fisicoquımica Biologica, Facultad de Ciencias, Universidad de la Republica, Montevideo, Uruguay Abstract Hydrogen sulfide (H S) is mainly known for its toxicity but has recently been shown to be produced endogenously in 2 mammalian tissues and to be associated with physiological regulatory functions. To better understand the role of biomembranes in modulating its biological distribution and effects; we measured the partition coefficient of H2S in models of biological membranes. The partition coefficients were found to be 2.160.2, 1.9 60.5 and 2.0 60.6 in n-octanol, hexane and dilauroylphosphatidylcholine liposome membranes relative to water, respectively (25uC). This two-fold higher concentration of H2S in the membrane translates into a rapid membrane permeability, Pm = 3 cm s21. We used a mathematical model in three dimensions to gain insight into the diffusion of total sulfide in tissues. This model shows that the sphere of action of sulfide produced by a single cell expands to involve more than 200 neighboring cells, and that the resistance imposed by