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1.
Med Gas Res ; 14(3): 89-95, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-39073335

RESUMEN

The Michael J. Fox Foundation has been funding research on Parkinson's disease for 35 years, but has yet to find a cure. This is due to a problem with the philosophy behind the development of modern medical treatments. In this paper, we will introduce "smart medicine" with a substance that can solve all the problems of central nervous system drugs. The substance is the smallest diatomic molecule, the hydrogen molecule. Due to their size, hydrogen molecules can easily penetrate the cell membrane and enter the brain. In the midbrain of Parkinson's disease patients, hydroxyl radicals generated by the Fenton reaction cause a chain reaction of oxidation of dopamine, but hydrogen entering the midbrain can convert the hydroxyl radicals into water molecules and inhibit the oxidation of dopamine. In this paper, we focus on the etiology of neurological diseases, especially Parkinson's disease, and present a case in which hydrogen inhalation improves the symptoms of Parkinson's disease, such as body bending and hand tremor. And we confidently state that if Michael J. Fox encountered "smart medicine" that could be realized with molecular hydrogen, he would not be a "lucky man" but a "super-lucky man."


Asunto(s)
Hidrógeno , Enfermedad de Parkinson , Enfermedad de Parkinson/terapia , Enfermedad de Parkinson/tratamiento farmacológico , Humanos , Hidrógeno/química , Hidrógeno/administración & dosificación , Administración por Inhalación , Encéfalo/metabolismo , Masculino
2.
Antiviral Res ; 229: 105956, 2024 09.
Artículo en Inglés | MEDLINE | ID: mdl-38969237

RESUMEN

Baloxavir marboxil (baloxavir), approved as an anti-influenza drug in Japan in March 2018, can induce reduced therapeutic effectiveness due to PA protein substitutions. We assessed PA substitutions in clinical samples from influenza-infected children and adults pre- and post-baloxavir treatment, examining their impact on fever and symptom duration. During the 2022-2023 influenza season, the predominant circulating influenza subtype detected by cycling-probe RT-PCR was A(H3N2) (n = 234), with a minor circulation of A(H1N1)pdm09 (n = 10). Of the 234 influenza A(H3N2) viruses collected prior to baloxavir treatment, 2 (0.8%) viruses carry PA/I38T substitution. One virus was collected from a toddler and one from an adult, indicating the presence of viruses with reduced susceptibility to baloxavir, without prior exposure to the drug. Of the 54 paired influenza A(H3N2) viruses collected following baloxavir treatment, 8 (14.8%) viruses carried E23 K/G, or I38 M/T substitutions in PA. Variant calling through next-generation sequencing (NGS) showed varying proportions (6-100 %), a polymorphism and a mixture of PA/E23 K/G, and I38 M/T substitutions in the clinical samples. These eight viruses were obtained from children aged 7-14 years, with a median fever duration of 16.7 h and a median symptom duration of 93.7 h, which were similar to those of the wild type. However, the delayed viral clearance associated with the emergence of PA substitutions was observed. No substitutions conferring resistance to neuraminidase inhibitors were detected in 37 paired samples collected before and following oseltamivir treatment. These findings underscore the need for ongoing antiviral surveillance, informing public health strategies and clinical antiviral recommendations for seasonal influenza.


Asunto(s)
Sustitución de Aminoácidos , Antivirales , Dibenzotiepinas , Farmacorresistencia Viral , Subtipo H3N2 del Virus de la Influenza A , Gripe Humana , Morfolinas , Piridonas , Triazinas , Proteínas Virales , Humanos , Dibenzotiepinas/uso terapéutico , Dibenzotiepinas/farmacología , Gripe Humana/tratamiento farmacológico , Gripe Humana/virología , Subtipo H3N2 del Virus de la Influenza A/genética , Subtipo H3N2 del Virus de la Influenza A/efectos de los fármacos , Subtipo H3N2 del Virus de la Influenza A/enzimología , Triazinas/uso terapéutico , Triazinas/farmacología , Japón , Antivirales/farmacología , Antivirales/uso terapéutico , Morfolinas/uso terapéutico , Farmacorresistencia Viral/genética , Niño , Adulto , Preescolar , Adolescente , Proteínas Virales/genética , ARN Polimerasa Dependiente del ARN/genética , Femenino , Masculino , Tiepinas/uso terapéutico , Tiepinas/farmacología , Lactante , Persona de Mediana Edad , Estaciones del Año , Piridinas/uso terapéutico , Piridinas/farmacología , Adulto Joven , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H1N1 del Virus de la Influenza A/efectos de los fármacos , Anciano
4.
Biomedicines ; 11(10)2023 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-37893190

RESUMEN

As diabetes rates surge globally, there is a corresponding rise in the number of patients suffering from diabetic kidney disease (DKD), a common complication of diabetes. DKD is a significant contributor to chronic kidney disease, often leading to end-stage renal failure. However, the effectiveness of current medical treatments for DKD leaves much to be desired. Molecular hydrogen (H2) is an antioxidant that selectively reduces hydroxyl radicals, a reactive oxygen species with a very potent oxidative capacity. Recent studies have demonstrated that H2 not only possesses antioxidant properties but also exhibits anti-inflammatory effects, regulates cell lethality, and modulates signal transduction. Consequently, it is now being utilized in clinical applications. Many factors contribute to the onset and progression of DKD, with mitochondrial dysfunction, oxidative stress, and inflammation being strongly implicated. Recent preclinical and clinical trials reported that substances with antioxidant properties may slow the progression of DKD. Hence, we undertook a comprehensive review of the literature focusing on animal models and human clinical trials where H2 demonstrated effectiveness against a variety of renal diseases. The collective evidence from this literature review, along with our previous findings, suggests that H2 may have therapeutic benefits for patients with DKD by enhancing mitochondrial function. To substantiate these findings, future large-scale clinical studies are needed.

5.
Med Gas Res ; 13(3): 108-111, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36571374

RESUMEN

Intestinal bacteria can be classified into "beneficial bacteria" and "harmful bacteria." However, it is difficult to explain the mechanisms that make "beneficial bacteria" truly beneficial to human health. This issue can be addressed by focusing on hydrogen-producing bacteria in the intestines. Although it is widely known that molecular hydrogen can react with hydroxyl radicals, generated in the mitochondria, to protect cells from oxidative stress, the beneficial effects of hydrogen are not fully pervasive because it is not generally thought to be metabolized in vivo. In recent years, it has become clear that there is a close relationship between the amount of hydrogen produced by intestinal bacteria and various diseases, and this report discusses this relationship.


Asunto(s)
Hidrógeno , Estrés Oxidativo , Humanos , Hidrógeno/farmacología , Radical Hidroxilo , Bacterias
6.
Med Gas Res ; 13(2): 43-48, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36204781

RESUMEN

Despite the fact that we have reported on the dangers of the explosion of hydrogen gas inhalers, hydrogen gas inhalers with explosive hazards are, as a matter of fact, still being sold today. In this study, we investigated past reports of hydrogen gas inhaler explosion accidents to clarify the causes of these explosion incidents. As a result of this investigation, we found that the central cause was the leakage of hydrogen gas inside the hydrogen gas inhaler. Although it is said that the explosive concentration of hydrogen is between 10% and 75%, and that the gas does not explode above 75% due to the lack of oxygen, we confirmed through a series of ignition experiments that explosions can occur even in hydrogen gas inhalers that produce 100% hydrogen gas. Some manufacturers of such highly concentrated hydrogen gas inhalers claim that the high concentration and purity of hydrogen is safe and that there is no risk of explosion. We believe that manufacturing or selling such products that pose a risk of explosion or detonation is a violation of social justice. This paper presents ideas for selecting safe hydrogen gas inhalers based on a survey of past accident cases.


Asunto(s)
Explosiones , Hidrógeno , Accidentes , Nebulizadores y Vaporizadores , Oxígeno
7.
Med Gas Res ; 13(2): 89-91, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36204788

RESUMEN

Most of the drugs used in modern medical treatments are symptomatic treatments and are far from being a cure for the diseases. The adverse effects are unavoidable in the drugs in modern medical treatments. Molecular hydrogen (H2) has a remarkable therapeutic effect on various diseases, and many clinical studies have reported that H2 has no adverse effects. Therefore, H2 is a novel medical gas that is outside the concept of modern medical treatment. H2, unlike drugs, works on the root of many diseases by scavenging the two kinds of strong reactive oxygen species, hydroxyl radical (·OH) and peroxynitrite (ONOO-). Since the H2 alleviates the root of diseases and can treat many diseases at the same time, the medical application of H2 may be called "machine gun therapy." In this review, we demonstrated that the root of many diseases is based on ·OH-induced oxidative stress in the mitochondria, and at the same time, the root of chronic inflammation is also attributed to ·OH.


Asunto(s)
Hidrógeno , Ácido Peroxinitroso , Hidrógeno/farmacología , Hidrógeno/uso terapéutico , Radical Hidroxilo , Estrés Oxidativo , Ácido Peroxinitroso/farmacología , Especies Reactivas de Oxígeno
8.
Front Neurol ; 13: 841310, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35493814

RESUMEN

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a disorder that is characterized by fatigue that persists for more than 6 months, weakness, sleep disturbances, and cognitive dysfunction. There are multiple possible etiologies for ME/CFS, among which mitochondrial dysfunction plays a major role in abnormal energy metabolism. The potential of many substances for the treatment of ME/CFS has been examined; however, satisfactory outcomes have not yet been achieved. The development of new substances for curative, not symptomatic, treatments is desired. Molecular hydrogen (H2) ameliorates mitochondrial dysfunction by scavenging hydroxyl radicals, the most potent oxidant among reactive oxygen species. Animal experiments and clinical trials reported that H2 exerted ameliorative effects on acute and chronic fatigue. Therefore, we conducted a literature review on the mechanism by which H2 improves acute and chronic fatigue in animals and healthy people and showed that the attenuation of mitochondrial dysfunction by H2 may be involved in the ameliorative effects. Although further clinical trials are needed to determine the efficacy and mechanism of H2 gas in ME/CFS, our literature review suggested that H2 gas may be an effective medical gas for the treatment of ME/CFS.

9.
Int J Mol Sci ; 22(16)2021 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-34445428

RESUMEN

While many antitumor drugs have yielded unsatisfactory therapeutic results, drugs are one of the most prevalent therapeutic measures for the treatment of cancer. The development of cancer largely results from mutations in nuclear DNA, as well as from those in mitochondrial DNA (mtDNA). Molecular hydrogen (H2), an inert molecule, can scavenge hydroxyl radicals (·OH), which are known to be the strongest oxidizing reactive oxygen species (ROS) in the body that causes these DNA mutations. It has been reported that H2 has no side effects, unlike conventional antitumor drugs, and that it is effective against many diseases caused by oxidative stress and chronic inflammation. Recently, there has been an increasing number of papers on the efficacy of H2 against cancer and its effects in mitigating the side effects of cancer treatment. In this review, we demonstrate the efficacy and safety of H2 as a novel antitumor agent and show that its mechanisms may not only involve the direct scavenging of ·OH, but also other indirect biological defense mechanisms via the regulation of gene expression.


Asunto(s)
Antineoplásicos/farmacología , Hidrógeno/farmacología , Neoplasias/genética , Antineoplásicos/uso terapéutico , Ensayos Clínicos como Asunto , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Hidrógeno/uso terapéutico , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo
10.
Int J Mol Sci ; 22(13)2021 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-34281264

RESUMEN

Mibyou, or pre-symptomatic diseases, refers to state of health in which a disease is slowly developing within the body yet the symptoms are not apparent. Common examples of mibyou in modern medicine include inflammatory diseases that are caused by chronic inflammation. It is known that chronic inflammation is triggered by the uncontrolled release of proinflammatory cytokines by neutrophils and macrophages in the innate immune system. In a recent study, it was shown that molecular hydrogen (H2) has the ability to treat chronic inflammation by eliminating hydroxyl radicals (·OH), a mitochondrial reactive oxygen species (ROS). In doing so, H2 suppresses oxidative stress, which is implicated in several mechanisms at the root of chronic inflammation, including the activation of NLRP3 inflammasomes. This review explains these mechanisms by which H2 can suppress chronic inflammation and studies its applications as a protective agent against different inflammatory diseases in their pre-symptomatic state. While mibyou cannot be detected nor treated by modern medicine, H2 is able to suppress the pathogenesis of pre-symptomatic diseases, and thus exhibits prospects as a novel protective agent.


Asunto(s)
Enfermedades Asintomáticas , Hidrógeno/farmacología , Sustancias Protectoras/farmacología , Enfermedad de Alzheimer/prevención & control , Animales , Enfermedad Crónica , Diabetes Mellitus Tipo 2/prevención & control , Depuradores de Radicales Libres/farmacología , Hepatitis/prevención & control , Humanos , Hipertensión/prevención & control , Inflamación/prevención & control , Modelos Biológicos , Neoplasias/prevención & control , Estrés Oxidativo , Enfermedad de Parkinson/prevención & control , Insuficiencia Renal Crónica/prevención & control
11.
Int J Mol Sci ; 22(5)2021 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-33806292

RESUMEN

Mitochondria are the largest source of reactive oxygen species (ROS) and are intracellular organelles that produce large amounts of the most potent hydroxyl radical (·OH). Molecular hydrogen (H2) can selectively eliminate ·OH generated inside of the mitochondria. Inflammation is induced by the release of proinflammatory cytokines produced by macrophages and neutrophils. However, an uncontrolled or exaggerated response often occurs, resulting in severe inflammation that can lead to acute or chronic inflammatory diseases. Recent studies have reported that ROS activate NLRP3 inflammasomes, and that this stimulation triggers the production of proinflammatory cytokines. It has been shown in literature that H2 can be based on the mechanisms that inhibit mitochondrial ROS. However, the ability for H2 to inhibit NLRP3 inflammasome activation via mitochondrial oxidation is poorly understood. In this review, we hypothesize a possible mechanism by which H2 inhibits mitochondrial oxidation. Medical applications of H2 may solve the problem of many chronic inflammation-based diseases, including coronavirus disease 2019 (COVID-19).


Asunto(s)
COVID-19/terapia , Hidrógeno/farmacología , Hidrógeno/uso terapéutico , Inflamación/terapia , Mitocondrias/fisiología , Animales , Enfermedad Crónica , Humanos , Inflamación/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/antagonistas & inhibidores , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Especies Reactivas de Oxígeno/antagonistas & inhibidores , Especies Reactivas de Oxígeno/metabolismo
12.
Int J Mol Sci ; 22(9)2021 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-33925430

RESUMEN

Although ionizing radiation (radiation) is commonly used for medical diagnosis and cancer treatment, radiation-induced damages cannot be avoided. Such damages can be classified into direct and indirect damages, caused by the direct absorption of radiation energy into DNA and by free radicals, such as hydroxyl radicals (•OH), generated in the process of water radiolysis. More specifically, radiation damage concerns not only direct damages to DNA, but also secondary damages to non-DNA targets, because low-dose radiation damage is mainly caused by these indirect effects. Molecular hydrogen (H2) has the potential to be a radioprotective agent because it can selectively scavenge •OH, a reactive oxygen species with strong oxidizing power. Animal experiments and clinical trials have reported that H2 exhibits a highly safe radioprotective effect. This paper reviews previously reported radioprotective effects of H2 and discusses the mechanisms of H2, not only as an antioxidant, but also in intracellular responses including anti-inflammation, anti-apoptosis, and the regulation of gene expression. In doing so, we demonstrate the prospects of H2 as a novel and clinically applicable radioprotective agent.


Asunto(s)
Hidrógeno/farmacología , Neoplasias/terapia , Traumatismos por Radiación/prevención & control , Protectores contra Radiación/farmacología , Animales , Antioxidantes/farmacología , Disfunción Cognitiva/etiología , Disfunción Cognitiva/prevención & control , Enfermedades Gastrointestinales/etiología , Enfermedades Gastrointestinales/prevención & control , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/efectos de la radiación , Humanos , Hidrógeno/uso terapéutico , Sistema Inmunológico/efectos de los fármacos , Sistema Inmunológico/efectos de la radiación , Masculino , Calidad de Vida , Protectores contra Radiación/uso terapéutico , Piel/efectos de los fármacos , Piel/efectos de la radiación , Espermatozoides/efectos de los fármacos , Espermatozoides/efectos de la radiación
14.
Med Gas Res ; 10(1): 47-49, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32189669

RESUMEN

It has been revealed that the cause of senescence and diseases is associated with the reactive oxygen species "hydroxyl radicals" (·OH). Senescence and diseases may be overcome as long as we can scavenge •OH mostly produced in mitochondria. It is one and only one "molecular hydrogen" (H2) that can both penetrate into the mitochondria and scavenge the •OH. The H2 in the body can function in disease prevention and recovery. H2 gas is explosive so that a safe hydrogen inhaler has to be developed for home use. We would like to advocate the great use of H2.


Asunto(s)
Envejecimiento/efectos de los fármacos , Enfermedad , Hidrógeno/farmacología , Humanos
15.
Med Gas Res ; 9(3): 160-162, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31552881

RESUMEN

Production and excretion of hydrogen (H2) gas in human was reported in 1969, since then it has been regarded as non-toxic molecule. For preventive and therapeutic medical uses, a possible treatment for cancer was reported and another article was published on how H2 acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals. A variety of H2 gas inhalers have been available in the market for hospital and home uses. However, H2 is odorless and flammable or explosive ignited by static electricity. We have examined the safety of a variety of H2 gas concentrations from the viewpoint of flammability and explosion. We have also measured concentrations of H2 gas inhalers in the market respectively. This paper also details how to control H2 gas concentration for preventing explosions.


Asunto(s)
Explosiones/prevención & control , Hidrógeno/química , Nebulizadores y Vaporizadores , Seguridad , Hidrógeno/uso terapéutico , Electricidad Estática
16.
Langmuir ; 28(36): 12982-8, 2012 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-22916823

RESUMEN

Cluster arrays composed of metal nanoparticles are promising for application in sensing devices because of their interesting surface plasmon characteristics. Herein, we report the spontaneous formation of cluster arrays of gold colloids on flat substrates by vertical-deposition convective self-assembly. In this technique, under controlled temperature, a hydrophilic substrate is vertically immersed in a colloid suspension. Cluster arrays form when the particle concentration is extremely low (in the order of 10(-6)-10(-8) v/v). These arrays are arranged in a hierarchically ordered structure, where the particles form clusters that are deposited at a certain separation distance from each other, to form "dotted" lines that are in turn aligned with a constant spacing. The size of the cluster can be controlled by varying the particle concentration and temperature while an equal separation distance is maintained between the lines formed by the clusters. Our technique thus demonstrates a one-step, template-free fabrication method for cluster arrays. In addition, through the direct observation of the assembly process, the spacing between the dotted lines is found to result from the "stick-and-slip" behavior of the meniscus tip, which is entirely different from the formation processes observed for the striped patterns, which we reported previously at higher particle concentrations. The difference in the meniscus behavior possibly comes from the difference in colloidal morphology at the meniscus tip. These results demonstrate the self-regulating characteristics of the convective self-assembly process to produce colloidal patterns, whose structure depends on particle concentration and temperature.

17.
J Biol Chem ; 286(28): 25256-64, 2011 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-21596743

RESUMEN

Chronic infection of Helicobacter pylori in the stomach mucosa with translocation of the bacterial cytotoxin-associated gene A (CagA) effector protein via the cag-Type IV secretion system (TFSS) into host epithelial cells are major risk factors for gastritis, gastric ulcers, and cancer. The blood group antigen-binding adhesin BabA mediates the adherence of H. pylori to ABO/Lewis b (Le(b)) blood group antigens in the gastric pit region of the human stomach mucosa. Here, we show both in vitro and in vivo that BabA-mediated binding of H. pylori to Le(b) on the epithelial surface augments TFSS-dependent H. pylori pathogenicity by triggering the production of proinflammatory cytokines and precancer-related factors. We successfully generated Le(b)-positive cell lineages by transfecting Le(b)-negative cells with several glycosyltransferase genes. Using these established cell lines, we found increased mRNA levels of proinflammatory cytokines (CCL5 and IL-8) as well as precancer-related factors (CDX2 and MUC2) after the infection of Le(b)-positive cells with WT H. pylori but not with babA or TFSS deletion mutants. This increased mRNA expression was abrogated when Le(b)-negative cells were infected with WT H. pylori. Thus, H. pylori can exploit BabA-Le(b) binding to trigger TFSS-dependent host cell signaling to induce the transcription of genes that enhance inflammation, development of intestinal metaplasia, and associated precancerous transformations.


Asunto(s)
Adhesinas Bacterianas/metabolismo , Adhesión Bacteriana/fisiología , Sistemas de Secreción Bacterianos/fisiología , Infecciones por Helicobacter/metabolismo , Helicobacter pylori/fisiología , Helicobacter pylori/patogenicidad , Adhesinas Bacterianas/genética , Animales , Células CHO , Quimiocina CCL5/biosíntesis , Quimiocina CCL5/genética , Cricetinae , Cricetulus , Perros , Mucosa Gástrica/inmunología , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patología , Eliminación de Gen , Infecciones por Helicobacter/genética , Proteínas de Homeodominio/biosíntesis , Proteínas de Homeodominio/genética , Humanos , Inflamación/genética , Inflamación/metabolismo , Inflamación/microbiología , Inflamación/patología , Interleucina-8/biosíntesis , Interleucina-8/genética , Antígenos del Grupo Sanguíneo de Lewis/genética , Antígenos del Grupo Sanguíneo de Lewis/metabolismo , Metaplasia/genética , Metaplasia/metabolismo , Metaplasia/microbiología , Metaplasia/patología , Mucina 2/biosíntesis , Mucina 2/genética , Lesiones Precancerosas/genética , Lesiones Precancerosas/metabolismo , Lesiones Precancerosas/microbiología , Lesiones Precancerosas/patología , Transducción de Señal/genética
18.
Plant Cell Environ ; 33(2): 174-87, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19906154

RESUMEN

To evaluate Ni dynamics at the subcellular level, the distribution and speciation of Ni were determined in wild-type (WT) and Ni-tolerant (NIT) tobacco BY-2 cell lines. When exposed to low but toxic levels of Ni, NIT cells were found to contain 2.5-fold more Ni (14% of whole-cell Ni values) in their cell walls than WT cells (6% of whole-cell Ni values). In addition to higher levels of Ni in the apoplast, a higher proportion (94%) of symplastic Ni was localized in the vacuoles of NIT cells than in the vacuoles of WT cells (81%). The concentration of cytosolic Ni in the NIT cells was significantly lower (18 nmol g(-1) FW) than that in the WT cells (85 nmol g(-1) FW). In silico simulation showed that 95% of vacuolar Ni was in the form of Ni-citrate complexes, and that free Ni(2+) was virtually absent in the NIT cells. On the other hand, the amount of free metal ions was markedly increased in WT cells because free citrate was depleted by chelation of Ni. A protoplast viability assay using BCECF-AM further demonstrated that the main mechanism that confers strong Ni tolerance was present in the symplast as opposed to the cell wall.


Asunto(s)
Pared Celular/metabolismo , Níquel/metabolismo , Nicotiana/metabolismo , Vacuolas/metabolismo , Línea Celular , Citratos/metabolismo , Modelos Químicos
20.
Chembiochem ; 7(10): 1582-9, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16921577

RESUMEN

Peroxide-bound heme species have been considered difficult to detect under physiological conditions because of their intrinsically transient properties. Cytochrome c552 (cyt c552), from Thermus thermophirus HB8, bearing a mutation to an alanine at Met69 (M69A) reacts with hydrogen peroxide (H(2)O(2)) to generate a detectable hydroperoxo-ferric heme ([Fe(3+)--OOH]) species at ambient temperature. EPR measurements during appropriate reaction periods reveal that the [Fe(3+)--OOH] species is in a preequilibrium state between the resting form of the cyt c552 variant and a subsequent intermediate, compound II with a protein radical. Addition of ascorbic acid to the reaction mixture of the cyt c552 variant and H(2)O(2) does not affect the formation of the [Fe(3+)--OOH] species,a result suggesting that the species is incompetent for the oxidation of even an oxidatively fragile substrate such as ascorbic acid. Another variant bearing an additional mutation to aspartic acid at Val49 (V49D/M69A) reveals that a highly hydrophobic heme cavity in cyt c552 accounts for the generation of the durable [Fe(3+)--OOH] species. The less polar environment inside the cavity is expected to prevent H(2)O from approaching the cavity. This would suppress protonation of the distal oxygen atom of the [Fe(3+)--OOH] species and retard subsequent dissociation of H(2)O from the OOH moiety.


Asunto(s)
Grupo Citocromo c/química , Hemo/química , Peróxido de Hidrógeno/química , Oxidantes/química , Antioxidantes/química , Antioxidantes/metabolismo , Ácido Ascórbico/química , Ácido Ascórbico/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Grupo Citocromo c/genética , Grupo Citocromo c/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Hemo/metabolismo , Peróxido de Hidrógeno/metabolismo , Mutación , Oxidantes/metabolismo , Oxidación-Reducción , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo
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