H₂O₂‐Diffusion Through Liposomes

Abstract

The toxicity of H2O2 suggests that it readily diffuses through cell membranes. The present paper demonstrates via a chromogenic peroxidase reaction that H2O2 can cross the lipid bilayer membrane without affecting the cell wall's integrity. In this demonstration, the chromogen ABTS was encapsulated with horseradish peroxidase into ovolecithin multilamellar liposomes. Upon the addition of dilute H2O2, the color was generated exclusively within the intact liposomes. Related results were observed with the AAP/DHBS chromogenic couple; however, this system is complicated by the small holes created by the phenol DHBS in the liposomal wall.

Modulatory effect of fatty acids on fungicidal activity, respiratory burst and TNF-α and IL-6 production in J774 murine macrophages

“…This reduction in O z2 2 content inside the cells may be due to the release to the extracellular medium or degradation by antioxidant enzymes. The superoxide anion is converted to H 2 O 2 by superoxide dismutase, and this latter reactive species is more stable and has more potent microbicidal potential (33) . Dietary supplementation with different FA has been shown to modulate ROS production by leucocytes.…”

An investigation ofhydrogen peroxide chemistry in surface waters of Vineyard Sound with H218O2 and 18O2

“…Various nonlight-dependent biological processes may lead to H,Oz production in seawater (Forman and Boveris 1982;Frimer et al 1983;Palenik et al 198 7;Palenik and Morel 1988). The production of H20, by the eucaryotic phytoplankter P. carterae (Palenik et al 1987) is from amino acid oxidation by cell-surface enzymes.…”

Effects of reagent and cell-generated hydrogen peroxide on the properties of low density lipoprotein.

“…For this reason, we undertook a detailed study of the role of a major oxidizing secretory product of phagocytic cells, H202. H202 is a relatively long lived, uncharged product of the reduction of molecular oxygen that can pass across biological membranes (8,9) and oxidize substrates at both intracellular and extracellular sites. In this paper we have examined the susceptibility of LDL to oxidation by known concentrations of chemical oxidants, by EC, and by the diverse group of reactive oxygen intermediates produced by monocytes.…”