The uncoupler desaspidin is labile in the presence of oxidants at alkaline pH values. It also undergoes chlorophyll-sensitized photooxidation at a more acid pH. The products of the oxidation appear to have negligible activity in inhibiting electron transfer and photophosphorylation.Failure of desaspidin to uncouple in the presence of oxidants used as cofactors of noncyclic electron flow is pres...

Chronic exposure to oxidants is associated with an increased incidence of malignancy; however, the mechanism(s) by which oxidants contribute to carcinogenesis is unknown. Since oncogene activation plays an important role in carcinogenesis, we hypothesized that hydroxyl radical-induced DNA damage might contribute to carcinogenesis by causing oncogene activation. The studies reported herein demon...

There is considerable interest in the role that mammalian heme peroxidase enzymes, primarily myeloperoxidase, eosinophil peroxidase and lactoperoxidase, may play in a wide range of human pathologies. This has been sparked by rapid developments in our understanding of the basic biochemistry of these enzymes, a greater understanding of the basic chemistry and biochemistry of the oxidants formed b...

Leakage of mitochondrial oxidants contributes to a variety of harmful conditions ranging from neurodegenerative diseases to cellular senescence. We describe here, however, a physiological and heretofore unrecognized role for mitochondrial oxidant release. Mitochondrial metabolism of pyruvate is demonstrated to activate the c-Jun N-terminal kinase (JNK). This metabolite-induced rise in cytosolic...

Reactive oxygen species (ROS) can damage proteins, cause lipid peroxidation, and react with DNA, ultimately resulting in harmful effects. Antioxidants constitute one of the defense systems used to neutralize pro-oxidants. Since pro-oxidants and antioxidants are found ubiquitously in nature, pro-and antioxidant effects of individual compounds and of mixtures receive much attention in scientific ...

Abstract Photosynthesis produces molecular oxygen, but it is the burial of organic carbon in sediments that has allowed this O 2 to accumulate Earth’s atmosphere. Yet many direct controls on preservation and have not been explored detail. For modern Earth, known reactive iron phases are important for preservation, suggesting availability particulate could be an factor oxygenation oceans atmosph...