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Antioxidant Activity of Ceruloplasmin
Published in Robert A. Greenwald, CRC Handbook of Methods for Oxygen Radical Research, 2018
Ceruloplasmin catalyzes the oxidation of a wide variety of polyamine and polyphenol substrates in vitro. However, with the possible exception of certain bioamines (for a review see Reference 3), these oxidations have no biological significance in vivo. A role for ceruloplasmin in vivo as a ferroxidase enzyme was first proposed by Osaki et al.4 The protein catalyzes oxidation of ferrous ions to the ferric state, the electrons being passed onto oxygen to form water. It has been proposed that this ferroxidase activity is essential for the incorporation of ferric ions into transferrin4 and possibly into ferritin.5 However, the role of ferroxidase activity in loading iron into iron proteins has been the subject of some debate. Several scientists have pointed out that ferrous ions readily autoxidize in aerobic solutions without the requirement for an enzyme (Equation 1):
Molecular Imaging of Reporter Genes
Published in Michel M. J. Modo, Jeff W. M. Bulte, Molecular and Cellular MR Imaging, 2007
Keren Ziv, Dorit Granot, Vicki Plaks, Batya Cohen, Michal Neeman
Ferritin is a ubiquitous, highly conserved iron storage protein.115 The spherical apoferritin shell is composed of 24 heavy and light chains of ferritin in variable proportions.124 The heavy chain has ferroxidase activity, i.e., catalytic oxidation of ferrous ions or ferrous complexes to the ferric state that promotes iron oxidation and incorporation.125 Overexpression of the H-chain ferritin resulted in the upregulation of the transferrin receptor and increased iron uptake by the transfected cells.18,126 The MRI properties of ferritin were the focus of extensive research and showed an anomaly at very low iron loading and a peculiar linear dependence on the magnetic field.127–129 The heavy chain of ferritin (h-ferritin) was applied as a reporter gene for MRI for monitoring tetracycline-inducible expression in C6 glioma tumors and transgenic mice,18,130 while adenoviral infection was demonstrated for the combination of both light (l-ferritin) and heavy chains of ferritin,131 as well as for the combination of h-ferritin with TfR.132
Copper Metabolism and Diseases of Copper Metabolism
Published in René Lontie, Copper Proteins and Copper Enzymes, 1984
The variety of states which lead to increased ceruloplasmin in itself suggests some important function for ceruloplasmin but its precise physiologic function or functions remains enigmatic. Summarizing the possible functions which have been discussed herein, ceruloplasmin does appear relevant to total copper homeostasis given the amount of copper involved in its daily turnover, and ceruloplasmin levels do increase when biliary secretion is impaired. Whether or not ceruloplasmin acts directly as a copper source for tissue remains unknown, but ceruloplasmin copper does ultimately appear in all tissues. The physiologic relevance of its ferroxidase activity also needs further verification.
LC-MS/MS: A sensitive and selective analytical technique to detect COVID-19 protein biomarkers in the early disease stage
Published in Expert Review of Proteomics, 2023
Siva Nageswara Rao Gajula, Ankita Sahebrao Khairnar, Pallavi Jock, Nikita Kumari, Kendre Pratima, Vijay Munjal, Pavan Kalan, Rajesh Sonti
Ferritin is a diagnostic biomarker for iron-deficiency anemia [124]. It is an intracellular globular protein that stores iron and releases it in a controlled fashion [125]. It consists of 24 protein subunits that form a hollow cage with multiple interactions of metal and protein [126]. Serum ferritin is essential for maintaining iron levels, ferroxidase activity, and immune and stress responses [127,128]. It is a critical mediator for severe hyperferritinemia due to its direct-immune suppression and inflammatory effects, resulting in a cytokine storm. Cytokine storm results in fatal outcomes and is a primary cause of death in COVID-19 patients [129,130]. The patients who tested COVID positive and have a previous history of diabetes show increased ferritin levels, posing a high risk [131–134]. Ferritin level was more elevated in non-survivors than in discharged patients [112]. Most studies found that patients recovered when ferritin levels were reduced by supplementation [134]. Ruscitti et al. developed an LC-MS method for determining ferritin levels [135] as a potential biomarker for predicting disease severity [136].
Copper deficiency, a rare but correctable cause of pancytopenia: a review of literature
Published in Expert Review of Hematology, 2022
Nayha Tahir, Aqsa Ashraf, Syed Hamza Bin Waqar, Abdul Rafae, Leela Kantamneni, Taha Sheikh, Rafiullah Khan
Copper deficiency is frequently associated with cytopenia, especially hypochromic anemia and neutropenia [71,84,90]. Impairment of ferroxidase enzyme results in impaired hemoglobin synthesis, resulting in anemia [10]. Bone marrow examination can be significant for ringed sideroblasts, indicating accumulation of mitochondrial iron [91]. Fatigue can be another side effect of copper deficiency which is mainly due to poor iron absorption [82,92]. Neurological abnormalities from copper deficiency have now been increasingly recognized in the studies. Copper is present in the basal ganglia, hippocampus, cerebellum, numerous synaptic membranes, and neurons [93]. The manifestations of copper deficiency resemble those of subacute combined degeneration of the spinal cord caused by vitamin B12 deficiency [94]. King et al. described a case where copper deficiency ultimately led to upper and lower extremity weakness and peripheral neuropathy [95]. Copper deficiency can cause skeletal abnormalities like brittle bones and osteogenesis imperfecta in children [96]. Other complications include impaired wound healing caused by deficiency of lysyl oxidase (copper-containing) enzyme, resulting in abnormal cross-linking of collagen fibers which is an essential step for wound healing [97]. Copper deficiency can also have a deleterious effect on humoral and cellular immunity [35].
Assessment of serum ferritin as a biomarker in COVID-19: bystander or participant? Insights by comparison with other infectious and non-infectious diseases
Published in Biomarkers, 2020
Kai Kappert, Amir Jahić, Rudolf Tauber
Ferritin is a spherical nanocage protein composed of 24 H- and L-subunits that is expressed in numerous tissues and cell types and is also present in body fluids particularly in blood plasma and serum (Arosio et al.2009, Wang et al.2010, Kell and Pretorius 2014). Depending on the type and the physiologic state of a cell or a tissue the stoichiometry of the H- and L-subunits in the 24-mer protein can vary, probably reflecting functional differences. Whereas in ferritin expressed in liver and spleen the L-subunit prevails, ferritin from brain, kidney and heart contains preferentially H-subunits (Arosio et al.2009). Serum ferritin is mainly composed of L-subunits indicating a hepatic origin, and is glycosylated (Cragg et al.1981). The best-studied function of cellular ferritin is storage of iron ions by the interaction with Fe(II), its oxidation to Fe(III) and its deposition in the cavity in a mineral form (Arosio et al.2009). Oxidation of Fe(II) to Fe(III) protects cells from Fe(II) catalysing the conversion of hydrogen peroxide, a product of mitochondrial oxidative respiration, into highly toxic hydroxyl free radicals in the Fenton reaction (Winterbourn 1995). Oxidation of Fe(II) to Fe(III) is catalysed by the ferroxidase activity of the H-subunit, while the L-subunit contributes to the incorporation of Fe(III) into the ferritin core. Reflecting the vital function of ferritin in iron metabolism, ferritin expression is strongly regulated by the iron response element/iron regulatory protein (IRE/IRP)-dependent mechanisms at the translational level (Kuhn 2015).