Phosphorylation of eukaryotic initiation factor-2 (eIF2) is an important mechanism mitigating cellular injury in response to diverse environmental stresses. While all eukaryotic organisms characterized to date contain an eIF2 kinase stress response pathway, the composition of eIF2 kinases differs, with mammals containing four distinct family members and the well-studied lower eukaryote Saccharo...

PURPOSE The lipofuscin fluorophore A2E is known to be an initiator of blue-light-induced apoptosis in retinal pigment epithelial cells (RPE). The purpose of this study was to evaluate the role of oxidative mechanisms in mediating the cellular damage. METHODS Human RPE (ARPE-19) cells that had accumulated A2E were exposed to blue light in the presence and absence of oxygen, and nonviable cells...

Microsomal cytochrome P-450 1A (CYP1A) in a vertebrate model (the teleost fish scup) is inactivated by the aryl hydrocarbon receptor agonist 3,39,4,49-tetrachlorobiphenyl (TCB). Here, the mechanism of CYP1A inactivation and its relationship to reactive oxygen species (ROS) formation were examined by using liver microsomes from scup and rat and expressed human CYP1As. In vitro inactivation of sc...

Here are some comments and useful suggestions after reading an article in mBio by Brown et al. entitled “Mechanisms underlying the exquisite sensitivity of Candida albicans to combinatorial cationic and oxidative stress that enhances the potent fungicidal activity of phagocytes” (1). In this paper, we are informed that a simultaneous exposure to 5 mM H2O2 and to cationic NaCl at 1 M is much mor...

Phenolic antioxidant butylated hydroxyanisole (BHA) is a commonly used food preservative with broad biological activities, including protection against acute toxicity of chemicals, modulation of macromolecule synthesis and immune response, induction of phase II detoxifying enzymes, and especially its potential tumor-promoting activities. Understanding the molecular basis underlying these divers...

on July 21, 2017. © 1995 American Association for Cancer Research. cancerres.aacrjournals.org Downloaded from CATALASE AS A GROWTH.PROMOTING FACFOR with the primary amino acid sequences obtained from human catalase cDNA (Table 1). It was of note that the lysine residue, which is hydrolyzed by the lysyl endopeptidase, was found in just prior to the sequenced peptides. Catalase Activity of the PU...

Reactive oxygen species (ROS), such as superoxide and H(2)O(2), are capable of modifying vascular tone, although the response to ROS can vary qualitatively among vascular beds, experimental procedures, and species. Endothelin-1 (ET-1) induces superoxide production, which can be dismutated to H(2)O(2). The RhoA/Rho kinase pathway partially mediates ET-1-induced contraction and recently was impli...

The location of the Trp radical and the catalytic function of the [Fe(IV)═O Trp₁₉₁(•+)] intermediate in cytochrome c peroxidase (CcP) are well-established; however, the unambiguous identification of the site(s) for the formation of tyrosyl radical(s) and their possible biological roles remain elusive. We have now performed a systematic investigation of the location and reactivity of the Tyr rad...

PURPOSE To determine the ability of the aqueous humor to generate and degrade H2O2, the effect of environmental factors such as oxygen tension and temperature, and the constituents contributing to the observed results. METHODS Aqueous humor was carefully removed from bovine eyes within 3 hours of death. Standard and new techniques were used to follow H2O2 degradation and formation. Catalase a...

The basis of resistance to oxidative injury was studied in six murine tumor cell lines that differed 54-fold in their resistance to enzymatically generated H(2)0(2). The tumors varied 56.7-fold in their specific activity of catalase, 5.3-fold in glutathione peroxidase (GPO), 3.3-fold in glutathione reductase (GR), and 2.7-fold in glutathione. There was no correlation among the levels of the thr...