Reaction Process: Plant Reactome:R-OBA-9611432

Cell Death and immunity related metabolites

find 8 related metabolites which is associated with chemical reaction(pathway) Cell Death and immunity

H+ + O2.- ⟶ H2O2 + Oxygen

Guanosine diphosphate

[({[(2R,3S,4R,5R)-5-(2-amino-6-oxo-6,9-dihydro-3H-purin-9-yl)-3,4-dihydroxyoxolan-2-yl]methoxy}(hydroxy)phosphoryl)oxy]phosphonic acid

C10H15N5O11P2 (443.02433)


Guanosine diphosphate, also known as gdp or 5-diphosphate, guanosine, is a member of the class of compounds known as purine ribonucleoside diphosphates. Purine ribonucleoside diphosphates are purine ribobucleotides with diphosphate group linked to the ribose moiety. Guanosine diphosphate is slightly soluble (in water) and a moderately acidic compound (based on its pKa). Guanosine diphosphate can be found in a number of food items such as strawberry, onion-family vegetables, walnut, and scarlet bean, which makes guanosine diphosphate a potential biomarker for the consumption of these food products. Guanosine diphosphate can be found primarily in blood and cerebrospinal fluid (CSF). Guanosine diphosphate exists in all living species, ranging from bacteria to humans. In humans, guanosine diphosphate is involved in several metabolic pathways, some of which include betahistine h1-antihistamine action, fexofenadine h1-antihistamine action, clocinizine h1-antihistamine action, and bepotastine h1-antihistamine action. Guanosine diphosphate is also involved in several metabolic disorders, some of which include adenine phosphoribosyltransferase deficiency (APRT), canavan disease, gout or kelley-seegmiller syndrome, and pyruvate dehydrogenase complex deficiency. Moreover, guanosine diphosphate is found to be associated with epilepsy, subarachnoid hemorrhage, neuroinfection, and stroke. Guanosine diphosphate, abbreviated GDP, is a nucleoside diphosphate. It is an ester of pyrophosphoric acid with the nucleoside guanosine. GDP consists of the pyrophosphate group, the pentose sugar ribose, and the nucleobase guanine . Guanosine diphosphate, also known as 5-GDP or 5-diphosphate, guanosine, belongs to the class of organic compounds known as purine ribonucleoside diphosphates. These are purine ribobucleotides with diphosphate group linked to the ribose moiety. Guanosine diphosphate exists in all living species, ranging from bacteria to humans. In humans, guanosine diphosphate is involved in intracellular signalling through adenosine receptor A2B and adenosine. Outside of the human body, Guanosine diphosphate has been detected, but not quantified in several different foods, such as devilfish, java plums, green beans, almonds, and orange mints. Guanosine diphosphate is a purine ribonucleoside 5-diphosphate resulting from the formal condensation of the hydroxy group at the 5 position of guanosine with pyrophosphoric acid. COVID info from COVID-19 Disease Map, PDB, Protein Data Bank Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS

   

Guanosine triphosphate

({[({[(2R,3S,4R,5R)-5-(2-amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-3,4-dihydroxyoxolan-2-yl]methoxy}(hydroxy)phosphoryl)oxy](hydroxy)phosphoryl}oxy)phosphonic acid

C10H16N5O14P3 (522.9906626)


Guanosine-5-triphosphate (GTP) is a purine nucleoside triphosphate. It is one of the building blocks needed for the synthesis of RNA during the transcription process. Its structure is similar to that of the guanosine nucleoside, the only difference being that nucleotides like GTP have phosphates on their ribose sugar. GTP has the guanine nucleobase attached to the 1 carbon of the ribose and it has the triphosphate moiety attached to riboses 5 carbon. GTP is essential to signal transduction, in particular with G-proteins, in second-messenger mechanisms where it is converted to guanosine diphosphate (GDP) through the action of GTPases. Guanosine triphosphate, also known as 5-GTP or H4GTP, belongs to the class of organic compounds known as purine ribonucleoside triphosphates. These are purine ribonucleotides with a triphosphate group linked to the ribose moiety. Thus, a GTP-bound tubulin serves as a cap at the tip of microtubule to protect from depolymerization; and, once the GTP is hydrolyzed, the microtubule begins to depolymerize and shrink rapidly. Guanosine triphosphate exists in all living species, ranging from bacteria to humans. In humans, guanosine triphosphate is involved in intracellular signalling through adenosine receptor A2B and adenosine. Guanosine-5-triphosphate (GTP) is a purine nucleoside triphosphate. Outside of the human body, guanosine triphosphate has been detected, but not quantified in several different foods, such as mandarin orange (clementine, tangerine), coconuts, new zealand spinachs, sweet marjorams, and pepper (capsicum). Cyclic guanosine triphosphate (cGTP) helps cyclic adenosine monophosphate (cAMP) activate cyclic nucleotide-gated ion channels in the olfactory system. It also has the role of a source of energy or an activator of substrates in metabolic reactions, like that of ATP, but more specific. It is used as a source of energy for protein synthesis and gluconeogenesis. For instance, a GTP molecule is generated by one of the enzymes in the citric acid cycle. GTP is also used as an energy source for the translocation of the ribosome towards the 3 end of the mRNA. During microtubule polymerization, each heterodimer formed by an alpha and a beta tubulin molecule carries two GTP molecules, and the GTP is hydrolyzed to GDP when the tubulin dimers are added to the plus end of the growing microtubule. The importing of these proteins plays an important role in several pathways regulated within the mitochondria organelle, such as converting oxaloacetate to phosphoenolpyruvate (PEP) in gluconeogenesis. GTP is involved in energy transfer within the cell. Guanosine triphosphate (GTP) is a guanine nucleotide containing three phosphate groups esterified to the sugar moiety. GTP functions as a carrier of phosphates and pyrophosphates involved in channeling chemical energy into specific biosynthetic pathways. GTP activates the signal transducing G proteins which are involved in various cellular processes including proliferation, differentiation, and activation of several intracellular kinase cascades. Proliferation and apoptosis are regulated in part by the hydrolysis of GTP by small GTPases Ras and Rho. Another type of small GTPase, Rab, plays a role in the docking and fusion of vesicles and may also be involved in vesicle formation. In addition to its role in signal transduction, GTP also serves as an energy-rich precursor of mononucleotide units in the enzymatic biosynthesis of DNA and RNA. [HMDB]. Guanosine triphosphate is found in many foods, some of which are oat, star fruit, lingonberry, and linden. COVID info from PDB, Protein Data Bank, WikiPathways Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS

   

Nicotinamide adenine dinucleotide phosphate

{[(2R,3R,4R,5R)-2-(6-amino-9H-purin-9-yl)-5-[({[({[(2R,3S,4R,5R)-5-(3-carbamoyl-1,4-dihydropyridin-1-yl)-3,4-dihydroxyoxolan-2-yl]methoxy}(hydroxy)phosphoryl)oxy](hydroxy)phosphoryl}oxy)methyl]-4-hydroxyoxolan-3-yl]oxy}phosphonic acid

C21H30N7O17P3 (745.0911)


NADPH is the reduced form of NADP+, and NADP+ is the oxidized form of NADPH. Nicotinamide adenine dinucleotide phosphate (NADP) is a coenzyme composed of ribosylnicotinamide 5-phosphate (NMN) coupled with a pyrophosphate linkage to 5-phosphate adenosine 2,5-bisphosphate. NADP serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). NADP is formed through the addition of a phosphate group to the 2 position of the adenosyl nucleotide through an ester linkage (Dorland, 27th ed). This extra phosphate is added by the enzyme NAD+ kinase and removed via NADP+ phosphatase. NADP is also known as TPN (triphosphopyridine nucleotide) and it is an important cofactor used in anabolic reactions in all forms of cellular life. Examples include the Calvin cycle, cholesterol synthesis, fatty acid elongation, and nucleic acid synthesis (Wikipedia). Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5-phosphate (NMN) coupled by pyrophosphate linkage to the 5-phosphate adenosine 2,5-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed.) [HMDB]. NADPH is found in many foods, some of which are american pokeweed, rice, ginseng, and ostrich fern. COVID info from COVID-19 Disease Map Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS

   

NADP+

beta-Nicotinamide adenine dinucleotide phosphate oxidized form sodium salt hydrate

[C21H29N7O17P3]+ (744.0832754)


[Spectral] NADP+ (exact mass = 743.07545) and NAD+ (exact mass = 663.10912) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. COVID info from COVID-19 Disease Map Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS

   

Oxygen

Molecular oxygen

O2 (31.98983)


Oxygen is the third most abundant element in the universe after hydrogen and helium and the most abundant element by mass in the Earths crust. Diatomic oxygen gas constitutes 20.9\\% of the volume of air. All major classes of structural molecules in living organisms, such as proteins, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that comprise animal shells, teeth, and bone. Oxygen in the form of O2 is produced from water by cyanobacteria, algae and plants during photosynthesis and is used in cellular respiration for all living organisms. Green algae and cyanobacteria in marine environments provide about 70\\% of the free oxygen produced on earth and the rest is produced by terrestrial plants. Oxygen is used in mitochondria to help generate adenosine triphosphate (ATP) during oxidative phosphorylation. For animals, a constant supply of oxygen is indispensable for cardiac viability and function. To meet this demand, an adult human, at rest, inhales 1.8 to 2.4 grams of oxygen per minute. This amounts to more than 6 billion tonnes of oxygen inhaled by humanity per year. At a resting pulse rate, the heart consumes approximately 8-15 ml O2/min/100 g tissue. This is significantly more than that consumed by the brain (approximately 3 ml O2/min/100 g tissue) and can increase to more than 70 ml O2/min/100 g myocardial tissue during vigorous exercise. As a general rule, mammalian heart muscle cannot produce enough energy under anaerobic conditions to maintain essential cellular processes; thus, a constant supply of oxygen is indispensable to sustain cardiac function and viability. However, the role of oxygen and oxygen-associated processes in living systems is complex, and they and can be either beneficial or contribute to cardiac dysfunction and death (through reactive oxygen species). Reactive oxygen species (ROS) are a family of oxygen-derived free radicals that are produced in mammalian cells under normal and pathologic conditions. Many ROS, such as the superoxide anion (O2-)and hydrogen peroxide (H2O2), act within blood vessels, altering mechanisms mediating mechanical signal transduction and autoregulation of cerebral blood flow. Reactive oxygen species are believed to be involved in cellular signaling in blood vessels in both normal and pathologic states. The major pathway for the production of ROS is by way of the one-electron reduction of molecular oxygen to form an oxygen radical, the superoxide anion (O2-). Within the vasculature there are several enzymatic sources of O2-, including xanthine oxidase, the mitochondrial electron transport chain, and nitric oxide (NO) synthases. Studies in recent years, however, suggest that the major contributor to O2- levels in vascular cells is the membrane-bound enzyme NADPH-oxidase. Produced O2- can react with other radicals, such as NO, or spontaneously dismutate to produce hydrogen peroxide (H2O2). In cells, the latter reaction is an important pathway for normal O2- breakdown and is usually catalyzed by the enzyme superoxide dismutase (SOD). Once formed, H2O2 can undergo various reactions, both enzymatic and nonenzymatic. The antioxidant enzymes catalase and glutathione peroxidase act to limit ROS accumulation within cells by breaking down H2O2 to H2O. Metabolism of H2O2 can also produce other, more damaging ROS. For example, the endogenous enzyme myeloperoxidase uses H2O2 as a substrate to form the highly reactive compound hypochlorous acid. Alternatively, H2O2 can undergo Fenton or Haber-Weiss chemistry, reacting with Fe2+/Fe3+ ions to form toxic hydroxyl radicals (-.OH). (PMID: 17027622, 15765131) [HMDB]. Oxygen is found in many foods, some of which are soy bean, watermelon, sweet basil, and spinach. Oxygen is the third most abundant element in the universe after hydrogen and helium and the most abundant element by mass in the Earths crust. Diatomic oxygen gas constitutes 20.9\\% of the volume of air. All major classes of structural molecules in living organisms, such as proteins, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that comprise animal shells, teeth, and bone. Oxygen in the form of O2 is produced from water by cyanobacteria, algae and plants during photosynthesis and is used in cellular respiration for all living organisms. Green algae and cyanobacteria in marine environments provide about 70\\% of the free oxygen produced on earth and the rest is produced by terrestrial plants. Oxygen is used in mitochondria to help generate adenosine triphosphate (ATP) during oxidative phosphorylation. For animals, a constant supply of oxygen is indispensable for cardiac viability and function. To meet this demand, an adult human, at rest, inhales 1.8 to 2.4 grams of oxygen per minute. This amounts to more than 6 billion tonnes of oxygen inhaled by humanity per year. At a resting pulse rate, the heart consumes approximately 8-15 ml O2/min/100 g tissue. This is significantly more than that consumed by the brain (approximately 3 ml O2/min/100 g tissue) and can increase to more than 70 ml O2/min/100 g myocardial tissue during vigorous exercise. As a general rule, mammalian heart muscle cannot produce enough energy under anaerobic conditions to maintain essential cellular processes; thus, a constant supply of oxygen is indispensable to sustain cardiac function and viability. However, the role of oxygen and oxygen-associated processes in living systems is complex, and they and can be either beneficial or contribute to cardiac dysfunction and death (through reactive oxygen species). Reactive oxygen species (ROS) are a family of oxygen-derived free radicals that are produced in mammalian cells under normal and pathologic conditions. Many ROS, such as the superoxide anion (O2-)and hydrogen peroxide (H2O2), act within blood vessels, altering mechanisms mediating mechanical signal transduction and autoregulation of cerebral blood flow. Reactive oxygen species are believed to be involved in cellular signaling in blood vessels in both normal and pathologic states. The major pathway for the production of ROS is by way of the one-electron reduction of molecular oxygen to form an oxygen radical, the superoxide anion (O2-). Within the vasculature there are several enzymatic sources of O2-, including xanthine oxidase, the mitochondrial electron transport chain, and nitric oxide (NO) synthases. Studies in recent years, however, suggest that the major contributor to O2- levels in vascular cells is the membrane-bound enzyme NADPH-oxidase. Produced O2- can react with other radicals, such as NO, or spontaneously dismutate to produce hydrogen peroxide (H2O2). In cells, the latter reaction is an important pathway for normal O2- breakdown and is usually catalyzed by the enzyme superoxide dismutase (SOD). Once formed, H2O2 can undergo various reactions, both enzymatic and nonenzymatic. The antioxidant enzymes catalase and glutathione peroxidase act to limit ROS accumulation within cells by breaking down H2O2 to H2O. Metabolism of H2O2 can also produce other, more damaging ROS. For example, the endogenous enzyme myeloperoxidase uses H2O2 as a substrate to form the highly reactive compound hypochlorous acid. Alternatively, H2O2 can undergo Fenton or Haber-Weiss chemistry, reacting with Fe2+/Fe3+ ions to form toxic hydroxyl radicals (-.OH). (PMID: 17027622, 15765131). V - Various > V03 - All other therapeutic products > V03A - All other therapeutic products > V03AN - Medical gases

   

Hydrogen peroxide

Hydrogen peroxide (H2O2)

H2O2 (34.0054792)


Hydrogen peroxide (H2O2) is a very pale blue liquid that appears colourless in a dilute solution. H2O2 is slightly more viscous than water and is a weak acid. H2O2 is unstable and slowly decomposes in the presence of light. It has strong oxidizing properties and is, therefore, a powerful bleaching agent that is mostly used for bleaching paper. H2O2 has also found use as a disinfectant and as an oxidizer. H2O2 in the form of carbamide peroxide is widely used for tooth whitening (bleaching), both in professionally- and in self-administered products. H2O2 is a well-documented component of living cells and is a normal metabolite of oxygen in the aerobic metabolism of cells and tissues. A total of 31 human cellular H2O2 generating enzymes has been identified so far (PMID: 25843657). H2O2 plays important roles in host defence and oxidative biosynthetic reactions. At high levels (>100 nM) H2O2 is toxic to most cells due to its ability to non-specifically oxidize proteins, membranes and DNA, leading to general cellular damage and dysfunction. However, at low levels (<10 nM), H2O2 functions as a signalling agent, particularly in higher organisms. In plants, H2O2 plays a role in signalling to cause cell shape changes such as stomatal closure and root growth. As a messenger molecule in vertebrates, H2O2 diffuses through cells and tissues to initiate cell shape changes, to drive vascular remodelling, and to activate cell proliferation and recruitment of immune cells. H2O2 also plays a role in redox sensing, signalling, and redox regulation (PMID: 28110218). This is normally done through molecular redox “switches” such as thiol-containing proteins. The production and decomposition of H2O2 are tightly regulated (PMID: 17434122). In humans, H2O2 can be generated in response to various stimuli, including cytokines and growth factors. H2O2 is degraded by several enzymes including catalase and superoxide dismutase (SOD), both of which play important roles in keeping the amount of H2O2 in the body below toxic levels. H2O2 also appears to play a role in vitiligo. Vitiligo is a skin pigment disorder leading to patchy skin colour, especially among dark-skinned individuals. Patients with vitiligo have low catalase levels in their skin, leading to higher levels of H2O2. High levels of H2O2 damage the epidermal melanocytes, leading to a loss of pigment (PMID: 10393521). Accumulating evidence suggests that hydrogen peroxide H2O2 plays an important role in cancer development. Experimental data have shown that cancer cells produce high amounts of H2O2. An increase in the cellular levels of H2O2 has been linked to several key alterations in cancer, including DNA changes, cell proliferation, apoptosis resistance, metastasis, angiogenesis and hypoxia-inducible factor 1 (HIF-1) activation (PMID: 17150302, 17335854, 16677071, 16607324, 16514169). H2O2 is found in most cells, tissues, and biofluids. H2O2 levels in the urine can be significantly increased with the consumption of coffee and other polyphenolic-containing beverages (wine, tea) (PMID: 12419961). In particular, roasted coffee has high levels of 1,2,4-benzenetriol which can, on its own, lead to the production of H2O2. Normal levels of urinary H2O2 in non-coffee drinkers or fasted subjects are between 0.5-3 uM/mM creatinine whereas, for those who drink coffee, the levels are between 3-10 uM/mM creatinine (PMID: 12419961). It is thought that H2O2 in urine could act as an antibacterial agent and that H2O2 is involved in the regulation of glomerular function (PMID: 10766414). A - Alimentary tract and metabolism > A01 - Stomatological preparations > A01A - Stomatological preparations > A01AB - Antiinfectives and antiseptics for local oral treatment D - Dermatologicals > D08 - Antiseptics and disinfectants > D08A - Antiseptics and disinfectants S - Sensory organs > S02 - Otologicals > S02A - Antiinfectives > S02AA - Antiinfectives It is used in foods as a bleaching agent, antimicrobial agent and oxidising agent C254 - Anti-Infective Agent > C28394 - Topical Anti-Infective Agent D009676 - Noxae > D016877 - Oxidants > D010545 - Peroxides D000890 - Anti-Infective Agents

   

Superoxide

Superoxide anion radical

O2- (31.98983)


Superoxide is the anionic form O2. It is important as the product of the one-electron reduction of dioxygen (oxygen gas), which occurs widely in nature. With one unpaired electron, the superoxide ion is a free radical. It is also paramagnetic. The biological toxicity of superoxide is due to its capacity to inactivate iron-sulfur cluster containing enzymes (which are critical in a wide variety of metabolic pathways), thereby liberating free iron in the cell, which can undergo fenton-chemistry and generate the highly reactive hydroxyl radical. In its HO2 form, superoxide can also initiate lipid peroxidation of polyunsaturated fatty acids. It also reacts with carbonyl compounds and halogenated carbons to create toxic peroxy radicals. As such, superoxide is a main cause of oxidative stress. Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to Methemoglobin. Because superoxide is toxic, nearly all organisms living in the presence of oxygen contain isoforms of the superoxide scavenging enzyme, superoxide dismutase, or SOD. SOD is an extremely efficient enzyme; it catalyzes the neutralization of superoxide nearly as fast as the two can diffuse together spontaneously in solution. Genetic inactivation ("knockout") of SOD produces deleterious phenotypes in organisms ranging from bacteria to mice. The latter species dies around 21 days after birth if the mitochondrial variant of SOD (Mn-SOD) is inactivated, and suffers from multiple pathologies, including reduced lifespan, liver cancer, muscle atrophy, cataracts and female infertility when the cytoplasmic (Cu, Zn -SOD) variant is inactivated. With one unpaired electron, the superoxide ion is a free radical and therefore paramagnetic. In living organisms, superoxide dismutase protects the cell from the deleterious effects of superoxides. Superoxide is the anionic form O2. It is important as the product of the one-electron reduction of dioxygen (oxygen gas), which occurs widely in nature. With one unpaired electron, the superoxide ion is a free radical. It is also paramagnetic. The biological toxicity of superoxide is due to its capacity to inactivate iron-sulfur cluster containing enzymes (which are critical in a wide variety of metabolic pathways), thereby liberating free iron in the cell, which can undergo fenton-chemistry and generate the highly reactive hydroxyl radical. In its HO2 form, superoxide can also initiate lipid peroxidation of polyunsaturated fatty acids. It also reacts with carbonyl compounds and halogenated carbons to create toxic peroxy radicals. As such, superoxide is a main cause of oxidative stress.; Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to Methemoglobin. D009676 - Noxae > D016877 - Oxidants > D013481 - Superoxides D009676 - Noxae > D016877 - Oxidants > D010545 - Peroxides

   

Hydrogen Ion

Hydrogen cation

H+ (1.0078246)


Hydrogen ion, also known as proton or h+, is a member of the class of compounds known as other non-metal hydrides. Other non-metal hydrides are inorganic compounds in which the heaviest atom bonded to a hydrogen atom is belongs to the class of other non-metals. Hydrogen ion can be found in a number of food items such as lowbush blueberry, groundcherry, parsley, and tarragon, which makes hydrogen ion a potential biomarker for the consumption of these food products. Hydrogen ion exists in all living organisms, ranging from bacteria to humans. In humans, hydrogen ion is involved in several metabolic pathways, some of which include cardiolipin biosynthesis cl(i-13:0/a-25:0/a-21:0/i-15:0), cardiolipin biosynthesis cl(a-13:0/a-17:0/i-13:0/a-25:0), cardiolipin biosynthesis cl(i-12:0/i-13:0/a-17:0/a-15:0), and cardiolipin biosynthesis CL(16:1(9Z)/22:5(4Z,7Z,10Z,13Z,16Z)/18:1(11Z)/22:5(7Z,10Z,13Z,16Z,19Z)). Hydrogen ion is also involved in several metabolic disorders, some of which include de novo triacylglycerol biosynthesis TG(20:3(8Z,11Z,14Z)/22:6(4Z,7Z,10Z,13Z,16Z,19Z)/22:5(7Z,10Z,13Z,16Z,19Z)), de novo triacylglycerol biosynthesis TG(18:2(9Z,12Z)/20:0/20:4(5Z,8Z,11Z,14Z)), de novo triacylglycerol biosynthesis TG(18:4(6Z,9Z,12Z,15Z)/18:3(9Z,12Z,15Z)/18:4(6Z,9Z,12Z,15Z)), and de novo triacylglycerol biosynthesis TG(24:0/20:5(5Z,8Z,11Z,14Z,17Z)/24:0). A hydrogen ion is created when a hydrogen atom loses or gains an electron. A positively charged hydrogen ion (or proton) can readily combine with other particles and therefore is only seen isolated when it is in a gaseous state or a nearly particle-free space. Due to its extremely high charge density of approximately 2×1010 times that of a sodium ion, the bare hydrogen ion cannot exist freely in solution as it readily hydrates, i.e., bonds quickly. The hydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes. Depending on the charge of the ion, two different classes can be distinguished: positively charged ions and negatively charged ions . Hydrogen ion is recommended by IUPAC as a general term for all ions of hydrogen and its isotopes. Depending on the charge of the ion, two different classes can be distinguished: positively charged ions and negatively charged ions. Under aqueous conditions found in biochemistry, hydrogen ions exist as the hydrated form hydronium, H3O+, but these are often still referred to as hydrogen ions or even protons by biochemists. [Wikipedia])