Faculty Collaboration Database

Reactivity of photochemically-generated lipid hydroperoxides in cell membranes with glutathione peroxidase. Photochem Photobiol 1989 Feb;49(2):153-6

Date

02/01/1989

Pubmed ID

2523541

DOI

10.1111/j.1751-1097.1989.tb04089.x

Scopus ID

2-s2.0-0024616037 (requires institutional sign-in at Scopus site)   17 Citations

Abstract

The ability of glutathione peroxidase (Gpx) to catalyze the reductive inactivation of photochemically-generated lipid hydroperoxides (LOOHs) was investigated, using hematoporphyrin derivative (HPD) as a photosensitizing agent and erythrocyte ghosts as membrane targets. Glutathione peroxidase was reactive toward photoperoxidized membranes only after their exposure to phospholipase A2 (PLA2). Iodometrically-determined LOOH values were typically 30-40% greater than values measured by enzymatic assay using Gpx and glutathione reductase. A consistent result was obtained when photooxidized membranes were treated with PLA2 and GSH/Gpx followed by iodometric assay, viz. persistence of approximately 40% of the starting LOOH. Whereas photooxidized egg phosphatidylcholine liposomes underwent total LOOH loss when incubated with PLA2 and GSH/Gpx, no net loss was observed with photooxidized cholesterol/dimyristoyl-phosphatidylcholine liposomes. The results suggest that cholesterol hydroperoxides in ghost membranes account for the Gpx-resistant fraction of LOOHs.

Author List

Thomas JP, Girotti AW

Authors

Albert W. Girotti PhD Adjunct Professor in the Biochemistry department at Medical College of Wisconsin
James P. Thomas MD, PhD Professor in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Erythrocyte Membrane
Glutathione Peroxidase
Hematoporphyrin Derivative
Hematoporphyrins
Humans
Kinetics
Lipid Peroxides
Liposomes
Membrane Lipids
Phosphatidylcholines
Radiation-Sensitizing Agents