About: Oxygenase is a research topic. Over the lifetime, 1220 publications have been published within this topic receiving 53308 citations. The topic is also known as: oxygenase.
TL;DR: An overview of the physiology of CO is provided, the effects of CO gas and CO-releasing molecules in preclinical animal models of cardiovascular disease, inflammatory disorders and organ transplantation are summarized, and the development and therapeutic options for the exploitation of this simple gaseous molecule are discussed.
Abstract: Carbon monoxide (CO) is increasingly being accepted as a cytoprotective and homeostatic molecule with important signalling capabilities in physiological and pathophysiological situations. The endogenous production of CO occurs through the activity of constitutive (haem oxygenase 2) and inducible (haem oxygenase 1) haem oxygenases, enzymes that are responsible for the catabolism of haem. Through the generation of its products, which in addition to CO includes the bile pigments biliverdin, bilirubin and ferrous iron, the haem oxygenase 1 system also has an obligatory role in the regulation of the stress response and in cell adaptation to injury. This Review provides an overview of the physiology of CO, summarizes the effects of CO gas and CO-releasing molecules in preclinical animal models of cardiovascular disease, inflammatory disorders and organ transplantation, and discusses the development and therapeutic options for the exploitation of this simple gaseous molecule.
TL;DR: The kinetics and tissue distribution of the microsomal heme oxygenase suggest that it is of major importance in the physiological degradation of hemoglobin and other hemoproteins to bile pigment.
TL;DR: The observation of a high level of induction of the enzyme in cells from an organ not involved in hemoglobin breakdown strongly supports the proposal that the induction of heme oxygenase may be a general response to oxidant stress and constitutes an important cellular defense mechanism against oxidative damage.
Abstract: We have shown that UVA (320-380 nm) radiation, hydrogen peroxide, and sodium arsenite induce a stress protein of approximately 32 kDa in human skin fibroblasts. The synthesis and cloning of cDNA from arsenite-induced mRNA populations have now allowed us to unequivocally identify the 32-kDa protein as heme oxygenase. By mRNA analysis we have shown that the heme oxygenase gene is also induced in cultured human skin fibroblasts by UVA radiation, hydrogen peroxide, cadmium chloride, iodoacetamide, and menadione. The known antioxidant properties of heme catabolites taken together with the observation of a high level of induction of the enzyme in cells from an organ not involved in hemoglobin breakdown strongly supports the proposal that the induction of heme oxygenase may be a general response to oxidant stress and constitutes an important cellular defense mechanism against oxidative damage.
TL;DR: An extracellular lignin-degrading enzyme from the basidiomycete Phanerochaete chrysosporium Burdsall was purified to homogeneity by ion-exchange chromatography, finding that it is an oxygenase, unique in its requirement for H(2)O(2).
Abstract: An extracellular lignin-degrading enzyme from the basidiomycete Phanerochaete chrysosporium Burdsall was purified to homogeneity by ion-exchange chromatography. The 42,000-dalton ligninase contains one protoheme IX per molecule. It catalyzes, nonstereospecifically, several oxidations in the alkyl side chains of lignin-related compounds: Cα—Cβ cleavage in lignin-related compounds of the type aryl—CαHOH—CβHR—CγH2OH (R = -aryl or -O-aryl), oxidation of benzyl alcohols to aldehydes or ketones, intradiol cleavage in phenylglycol structures, and hydroxylation of benzylic methylene groups. It also catalyzes oxidative coupling of phenols, perhaps explaining the long-recognized association between phenol oxidation and lignin degradation. All reactions require H2O2. The Cα—Cβ cleavage and methylene hydroxylation reactions involve substrate oxygenation; the oxygen atom is from O2 and not H2O2. Thus the enzyme is an oxygenase, unique in its requirement for H2O2.
TL;DR: Molecular and biochemical evidence for a possible biosynthetic route using myo-inositol (MI) as the initial substrate is presented, suggesting the role of MI in AsA biosynthesis and the potential for using this gene for the agronomic and nutritional enhancement of crops.
Abstract: Two biosynthetic pathways for ascorbate (l-ascorbic acid [AsA]; vitamin C) in plants are presently known, the mannose/l-galactose pathway and an l-GalUA pathway. Here, we present molecular and biochemical evidence for a possible biosynthetic route using myo-inositol (MI) as the initial substrate. A MI oxygenase (MIOX) gene was identified in chromosome 4 (miox4) of Arabidopsis ecotype Columbia, and its enzymatic activity was confirmed in bacterially expressed recombinant protein. Miox4 was primarily expressed in flowers and leaves of wild-type Arabidopsis plants, tissues with a high concentration of AsA. Ascorbate levels increased 2- to 3-fold in homozygous Arabidopsis lines overexpressing the miox4 open reading frame, thus suggesting the role of MI in AsA biosynthesis and the potential for using this gene for the agronomic and nutritional enhancement of crops.