Calcium promotes membrane association of reticulocyte 15-lipoxygenase.
The reticulocyte 15-lipoxygenase (linoleate:oxygen oxidoreductase, EC 1.13.11.12) is implicated in oxidative damage to reticulocyte mitochondria before their elimination by degradation during maturation to the erythrocyte. A proportion of the 15-lipoxygenase sediments with the mitochondrial-rich stromal fraction of density-gradient-fractionated rabbit reticulocytes suggesting a physical association with mitochondria before their elimination. Ca2+ promotes binding of reticulocyte 15-lipoxygenase to isolated rat liver and reticulocyte mitochondria and 15-lipoxygenase-mediated lipid peroxidation of mitochondrial lipids and free linoleic acid. Association of reticulocyte 15-lipoxygenase with isolated mitochondria is not simply a consequence of Ca(2+)-induced swelling, but implies that Ca2+ mediates translocation of soluble lipoxygenase to mitochondrial membranes. Therefore, Ca2+ may have an important physiological role in the regulation of 15-lipoxygenase-mediated targeting of reticulocyte mitochondria for degradation.
Watson
A
A
Department of Biochemistry, University Medical School, Queen's Medical Centre, Nottingham, U.K.
Doherty
F J
FJ
D000818:Animals; D001093:Arachidonate 15-Lipoxygenase / Q000097:blood*; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002458:Cell Fractionation; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000201:enzymology*; D015227:Lipid Peroxidation; D008928:Mitochondria / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D011817:Rabbits; D051381:Rats; D012156:Reticulocytes / Q000201:enzymology*
D001093:Arachidonate 15-Lipoxygenase; D002118:Calcium