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Macronutrients
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Conjugated proteins or Heteroproteins consist of a simple protein combined with a nonprotein component. The nonprotein component is called a prosthetic group (36, 47). A protein without its prosthetic group is called an apoprotein. A protein molecule combined with its prosthetic group forms a heteroprotein. Prosthetic groups play an important role in the function of proteins. Conjugated proteins are classified according to the nature of their prosthetic groups. They include glycoproteins, lipoproteins, metalloproteins, hemoproteins, phosphoproteins, and so on. Glycoproteins contain a carbohydrate component. Lipoproteins are proteins containing lipid molecules such as cholesterol which are divided into High-Density Lipoprotein (HDL) or ‘good’ cholesterol and Low-Density Lipoprotein (LDL) or ‘bad’ cholesterol. Metalloproteins contain metal ions (iron, calcium, copper, zinc, and molybdenum). Phosphoproteins contain phosphate groups, while hemoproteins or chromoproteins possess heme groups such as hemoglobin. Hemoglobin is the metalloprotein containing iron for the transport of oxygen in the red blood cells of all mammals (36, 47).
Liver Diseases
Published in George Feuer, Felix A. de la Iglesia, Molecular Biochemistry of Human Disease, 2020
George Feuer, Felix A. de la Iglesia
The pathway of heme formation has been demonstrated a long time ago.414,510,511 All nitrogen atoms and eight carbon atoms of the heme molecule are derived from glycine, the remaining carbon atoms derive from succinate via the Krebs’ cycle. In the first step, glycine and succinate are combined, and two of the resulting δ-aminolevulinic acid molecules are condensed to give monopyrrole porphobilinogen. The next step is an enzymatic polymerization of four porphobilinogen units leading to the formation of uroporphyrinogen. Subsequently, decarboxylation yields coproporphyrinogen; a side chain modification transforms this compound to protoporphyrinogen IX and finally, the incorporation of ferrous ion gives rise to heme and the addition of a globin leads to hemoglobin459 (Figure 8). The heme molecule is the prostetic group of a variety of hemoproteins such as hemoglobin, myoglobin, cytochromes, catalase, peroxidase, and others.
Heme Oxygenase-1 in Kidney Health and Disease
Published in Shamim I. Ahmad, Handbook of Mitochondrial Dysfunction, 2019
Pu Duann, Elias A. Lianos, Pei-Hui Lin
Heme is an iron-containing porphyrin complex and constitutes the prosthetic group of several hemoproteins with important biological functions. Heme is synthesized in the mitochondria with protoporphyrins supplied from its precursor succinyl-CoA from mitochondria TCA (Kreb) cycle, which then subsequently exported out via the mitochondrial transporter ATP-binding cassette (ABC) B10 after biosynthesis (7). Hemes are most commonly recognized as components of hemoglobin from red blood cells (erythrocytes). Some other examples of hemoproteins include myoglobin (enriched in muscle), catalases, heme peroxidase, cytochromes, and endothelial nitric oxide synthase (eNOS) (8). The redox-active nature of iron makes heme critically involved in modulation of oxidating-reducing activities of hemoproteins which engaged in oxygen transport (hemoglobin) and storage (myoglobin), mitochondrial electron transfer and energy transformation (cytochromes), hydrogen peroxide activation (heme peroxidase) or inactivation (catalases) and nitro oxide synthesis (eNOS) (9). In physiology, significant level of heme could arise from the destruction of aged red blood cells. Because heme also catalyzes the formation of toxic reactive oxygen species (ROS) and free hydroxyl radicals to induce pro-oxidant and cytotoxic effects, level of “free-heme” must be tightly regulated. Disturbed heme metabolism causes mitochondrial decay, oxidative stress, and iron accumulation has been linked to age-related diseases (10).
Stabilization of Nrf2 leading to HO-1 activation protects against zinc oxide nanoparticles-induced endothelial cell death
Published in Nanotoxicology, 2021
Longbin Zhang, Liyong Zou, Xuejun Jiang, Shuqun Cheng, Jun Zhang, Xia Qin, Zhexue Qin, Chengzhi Chen, Zhen Zou
HO-1 has received considerable attention as a master protective sentinel, that plays a prominent role in different organs and tissues, as well as different pathological scenarios (Otterbein, Foresti, and Motterlini 2016; Satta et al. 2017). As the rate-limiting step in the catabolism of heme into bioactive signaling molecules, the main function of HO-1 is to degrade heme to generate carbon monoxide (CO) and biliverdin and with the simultaneous releasing of iron. These products induce signaling and cytoprotective activities that mitigate apoptosis and inflammation, regulate vasomotor tone, and exhibit antioxidant and immunomodulatory functions. In addition to generation of HO-1-derived products, the role of this enzyme is to counteract oxidative tissue injury triggered by free heme. Large amounts of heme can be released from specific hemoproteins upon oxidative stress, contributing to the amplification of cell and tissue injury (Gozzelino, Jeney, and Soares 2010). Although HO-1 is a crucial arbiter of oxidative stress and inflammatory responses, the precise mechanism of HO-1 in endothelial cell death induced by ZnONPs needs further investigation. Another interesting role of HO-1 may be related to the release of free iron ions upon its profound upregulation, which might trigger nonapoptotic, iron-dependent cell death, called ferroptosis (Dixon et al. 2012; Yang et al. 2014). Our group recently reported that ZnONPs could induce ferroptosis in endothelial cell death (Qin et al. 2021), however whether HO-1 is involved in this process needs further investigation.
Rhabdomyolysis, Methamphetamine, Amphetamine and MDMA Use: Associated Factors and Risks
Published in Journal of Dual Diagnosis, 2020
John R. Richards, Colin G. Wang, Roderick W. Fontenette, Rory P. Stuart, Kerry F. McMahon, Samuel D. Turnipseed
CK catalyzes the reversible reaction of creatine and ATP to form phosphocreatine and adenosine diphosphate (ADP). As such, CK is critical for maintaining cellular energy homeostasis in tissues with high energy demand, such as skeletal muscle, heart, and the central nervous system. Depletion of ATP results in increased permeability of the sarcolemma, the cellular membrane enclosing skeletal muscle fibers, with pathological elevation of sarcoplasmic calcium (Cervellin et al., 2017; Richards, 2000). Proteolytic and cytotoxic enzymes are then activated, which leads to cellular edema and rupture. Disruption of the sarcolemma results in release of myoglobin, a cytoplasmic hemoprotein found in skeletal and cardiac myocytes. Excess myoglobin precipitates in the kidney, causing renal tubular obstruction, direct nephrotoxicity, and acute renal failure. At the organ level, acute skeletal muscle edema may be restricted by surrounding fascia, leading to elevated compartment pressure, ischemia, and necrosis.
Dual effects include antioxidant and pro-oxidation of ascorbic acid on the redox properties of bovine hemoglobin
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Hemoglobin, a kind of heme protein, was extensively investigated during the past decades mainly due to its physiological function of oxygen binding and releasing in red blood cells. Previous research had shown that the hemoglobin could play critical effects in pathophysiology of some diseases or tissue dysfunctions [1]. Besides, another great potential application of hemoglobin is that the hemoglobin-derivates could be used for oxygen carriers, which were considered to be the most promising candidate of red blood cell substitutes and thus had been attracting more and more attentions [2,3]. The hemoglobin-based oxygen carriers (HBOCs) had been intensively studied as the candidates of blood substitutes and were proven to be effective in the treatment of ischemic diseases such as acute anemia [4], hemorrhagic shock [5], microcirculation dysfunctions [6] and so on.