title: Hydrogen peroxide permeation across liposomal membranes: a novel method to assess structural flaws in liposomes.
abstract: Hydrogen peroxide permeation across large multilamellar vesicles of defined and complex lipid composition was shown to obey precise kinetic relationships for the activity of the occluded catalase. Careful assay conditions precluded simultaneous peroxidative damage to the lipids. The kinetic data was consistent with a barrier role for the bilayer for hydrogen peroxide permeation. More interestingly, hydrogen peroxide permeation across liposomes of complex lipid mixtures exhibited osmotic inhibition of permeation of hydrogen peroxide. On the other hand, purified egg lecithin vesicles did not exhibit any effect of external osmolality on hydrogen peroxide permeation in an experimentally defined non-lytic zone of external osmolarity. These results argue in favour of a heterogeneous, heteroporous structure of bilayers with complex lipid composition.
authors.affiliation: Biotechnology Department of Zoology, University of Poona, Pune, India.
authors.forename: V
authors.initials: V
authors.lastname: Sitaramam
authors.forename: J C
authors.initials: JC
authors.lastname: Mathai
authors.forename: N M
authors.initials: NM
authors.lastname: Rao
authors.forename: L H
authors.initials: LH
authors.lastname: Block
mesh_terms: D000818:Animals; D001692:Biological Transport; D002374:Catalase; D002462:Cell Membrane; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007700:Kinetics; D008051:Lipid Bilayers; D015227:Lipid Peroxidation; D008081:Liposomes; D009995:Osmosis; D051381:Rats
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes; D006861:Hydrogen Peroxide; D002374:Catalase