Search results for "Phosphorylation"
showing 10 items of 975 documents
Regulatory features of glycogen phosphorylase from frog brain (Rana temporaria)
1985
1. Glycogen content and the activity of glycogen phosphorylase (GPase) are much higher in brain tissue of the Common frog (Rana temporaria) than in brain tissue of mammals and birds (Table 1). 2. In phosphate buffer GPase is extracted from frog orain in a form completely active without addition of AMP and has therefore to be regarded as phosphorylase a. Several procedures to extract the b-form of the enzyme from the tissue have been unsuccessful. In resting skeletal muscle predominantly the AMP dependent b-form is present (Table 1). 3. In vitro, however, the existence of the complete interconverting system can be demonstrated. If NaF (a phosphatase inhibitor) was omitted from the homogeniza…
Oxidative halogenation of substituted pyrroles with Cu(II). PartIII. Bromination and chlorination of 2-benzoylpyrrole
1992
The bromination of 2-benzoylpyrrole with copper(II) bromide in the homogeneous and the heterogeneous phase is described, giving 4- and 5-monobromo derivatives whose ratio decreases as the temperature is increased. The same reaction with copper(II) chloride in acetonitrile at 60° produces 5-chloro-2-benzoylpyrrole as the major product. 4,5-Dihalopyrroles in good yields are obtained with an excess of halogenating agent.
The Distribution of Carcinogen Metabolizing Enzymes in the Mouse Liver: Comparison of Parenchymal and Non-Parenchymal Cell Populations
1987
The distribution of aminopyrine N-demethylase (APND), ethoxy- resorufin O-deethylase (ERRD), epoxide hydrolase (EH) and glutathione transferase (GST) activities in parenchymal (PC) and non-parenchymal (NPC) cell populations of control and Aroclor 1254-treated C57BL/6N and DBA/2N mice was determined. Furthermore, the metabolism of benzo(a)- pyrene (BP) in PC and NPC of both Aroclor 1254-treated mice strains was examined. Measurable activities of all enzymes investigated were detected in control PC as well as NPC of both mice strains; in all instances the PC possessed greater enzyme activities than did the NPC. The PC and NPC of DBA/ 2N mice had significantly lower ERRD and EH activities than…
Posttranslational Processing of Human α2-HS Glycoprotein (Human Fetuin)
2008
α2-HS glycoprotein (α2-HS) is a major protein occuring in human blood and calciferous tissues. Due to extensive sequence identity, α2-HS has been grouped with the fetuins, a family of proteins that occur in fetal plasma in high concentrations. Native α2-HS undergoes a series of posttranslational modifications including proteolytic processing, multiple N-glycosylations and O-glycosylations, and sulfation of the carbohydrate side chains. Various two-chain forms of α2-HS have been prepared from human plasma, however, the single-chain precursor has not yet been isolated. Here, we have studied the biosynthesis of α2-HS by a human hepatoma cell line, HepG2. We demonstrate that a single-chain form…
Serum antinuclear autoantibodies are associated with measures of oxidative stress and lifestyle factors - analysis of LIPIDOGRAM2015 and LIPIDOGEN201…
2021
IntroductionOxidative stress is one of many factors suspected to promote antinuclear autoantibody (ANA) formation. Reactive oxygen species can induce changes in the antigenic structure of macromolecules, causing the immune system to treat them as “neo-antigens” and start production of autoantibodies. This study was designed to evaluate the relationship between oxidative stress markers, lifestyle factors and the detection of ANA.Material and methodsWe examined measures of oxidative stress indices of free-radical damage to lipids and proteins, such as total oxidant status (TOS), concentration of protein thiol groups (PSH), and malondialdehyde (MDA), activity of superoxide dismutase (SOD) in i…
Antioxidation and the Hypoxic Ventilatory Response
2012
Reactive oxygen species favor the reductive state of iron. Antioxidation, by depleting biologically active ferrous iron, could then have a stabilizing effect, akin to hypoxia, on HIF-1α; the process which controls the genetic responses to hypoxia. However, the influence of antioxidation on the hypoxic ventilatory responses (HVR) is unclear. In this study we set out to determine the influence of mangiferin, a natural polyphenolic compound present in mango trees, with strong antioxidant and iron chelating properties, on the HVR. The study was performed in awake Wistar rats. Acute HVR to 12% and 8% FiO2 before and 40 min after mangiferin (300 mg/kg, i.p.) pretreatment were recorded plethysmogr…
The Role of Mitochondrial Reactive Oxygen Species Formation for Age-Induced Vascular Dysfunction
2010
Aging is an important risk factor for the development of cardiovascular diseases, which can be accelerated by atherosclerosis, diabetes, hypercholesterolemia, or obesity. Vascular aging is mainly characterized by endothelial dysfunction, an alteration of endothelium-dependent signaling processes, and vascular remodeling. The underlying mechanisms include increased production of reactive oxygen species (ROS), inactivation of nitric oxide (•NO), and subsequent formation of reactive nitrogen and oxygen species (RNOS). Elevated RNOS may exhibit new messenger functions by posttranslational oxidative modification of intracellular regulatory proteins or lead to irreversible alterations of biologic…
Exercise-Induced Activation and Translocation of αB-Crystallin in Skeletal Muscle Depends upon Fiber Type and Oxidative Stress
2016
Alpha B-crystallin (CRYAB) is a member of the small heat shock proteins implicated in various biological functions, particularly in skeletal muscle tissue [1], where it results to be modulated following exercise-induced reactive oxygen species (ROS) [2]. In this work we aimed to analyse the CRYAB response to acute exercise with respect muscle fiber composition and to identify the underlying molecular mechanism by the utilization of the C2C12 “in vitro” cellular model. Our results highlighted as acute exercise determines a specific increase of phospho-CRYAB both in the red, but not white, gastrocnemius (GS), with an higher amount of oxidative and oxidative-glycolytic fibers, and in soleus (S…
Formation of covalent di-tyrosine dimers in recombinant α-synuclein
2015
Parkinson's disease is associated with fibril deposition in the diseased brain. Misfolding events of the intrinsically disordered synaptic protein α-synuclein are suggested to lead to the formation of transient oligomeric and cytotoxic species. The etiology of Parkinson's disease is further associated with mitochondrial dysfunction and formation of reactive oxygen species. Oxidative stress causes chemical modification of native α-synuclein, plausibly further influencing misfolding events. Here, we present evidence for the spontaneous formation of covalent di-tyrosine α-synuclein dimers in standard recombinant protein preparations, induced without extrinsic oxidative or nitrative agents. The…
Oxidative stress in diabetic retinopathy
2020
Diabetic retinopathy (DR) is the leading cause of acquired blindness in working adults worldwide. Biochemical changes in DR contribute to both the microscopic structural and functional changes in the retina. All these alterations result in retinal damage that can be assessed by funduscopy, optical coherence tomography (OCT), and angioOCT. Reactive oxygen species (ROS) overproduction in the mitochondria is considered a causal link between elevated glucose and biochemical abnormalities in the pathophysiology of DR. Moreover, oxidative-induced pathways also seem to provide positive feedback to ROS production, resulting in a vicious cycle. ROS can directly damage lipids, proteins, and DNA, lead…