Information about Urate
| Uric acid | |
|---|---|
) | |
| IUPAC name | 7,9-dihydro-1H-purine- 2,6,8(3H)-trione |
| Other names | 2,6,8 Trioxypurine |
| Identifiers | |
| CAS number | |
| SMILES | C12NC(=O)NC(=O)C=2NC(=O)N1 |
| Properties | |
| Molecular formula | C5H4N4O3 |
| Molar mass | 168g/mol |
| Appearance | White Crystals |
| Density | 1.87 |
| Melting point | decomposes on heating |
| Boiling point | N/A |
| Solubility in water | Slightly |
| Acidity (pKa) | 3.89 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 C, 100 kPa) | |
Metabolic processes
Xanthine oxidase oxidizes oxypurines such as xanthine and hypoxanthine to uric acid. In humans and higher primates, uric acid is the final oxidation product of purine catabolism. In most other mammals, the enzyme uricase further oxidizes uric acid to allantoin.[1] The loss of uricase in higher primates parallels the similar loss of the ability to synthesize ascorbic acid.[2] This may be because in higher primates uric acid (urate) partially replaces ascorbic acid.[3] Both urate and ascorbate are strong reducing agents (electron donors) and potent antioxidants. In humans, about half the antioxidant capacity of plasma comes from uric acid.Uric acid is also the end product of nitrogen catabolism in birds and reptiles. In such species, it is excreted in feces as a dry mass. While this compound is produced through a complex and energetically costly metabolic pathway (in comparison to other nitrogenated wastes such as urea or ammonia), its elimination minimizes water loss. It is therefore commonly found in the excretions of animals—such as the kangaroo rat—that live in very dry environments. The Dalmatian dog has a defect in uric acid metabolism resulting in decreased conversion to allantoin, so this breed excretes uric acid, and not allantoin, in the urine.
Medical issues
Humans produce only small quantities of uric acid. In human blood, uric acid concentrations between 3.6 mg/dL (~214µmol/L) and 8.3 mg/dL (~494µmol/L) (1mg/dL=59.48 µmol/L)[4] are considered normal by the American Medical Association, although significantly lower levels are common in vegetarians due to a decreased intake of purine-rich meat.[5]High Uric Acid
Gout
Excess serum accumulation of uric acid can lead to a type of arthritis known as gout.[6]Elevated (serum uric acid) level (hyperuricemia) can result from high intake of purine-rich foods, high fructose intake (regardless of fructose's low Glycemic Index (GI) value) and/or impaired excretion by the kidneys. Saturation levels of uric acid in blood may result in one form of kidney stones when the urate crystallizes in the kidney. Some patients with gout eventually get uric kidney stones.
Gout can occur where serum uric acid levels are as low as 6 mg/dL (~357µmol/L), but an individual can have serum values as high as 9.5 mg/dL (~565µmol/L) and not have gout[7] (no abstract available; levels reported at[8]).
Lesch-Nyhan syndrome
Lesch-Nyhan syndrome is also associated with very high serum uric acid levels.[9]Spasticity, involuntary movement and cognitive retardation as well as manifestations of gout are seen in cases of this syndrome.[10]
Cardiovascular disease
Although uric acid can act as an antioxidant, excess serum accumulation is implicated in cardiovascular diseaseHigh uric acid can cause kidney stones, gouts in joints, and disable the body to produce purines, which build up the genetic "blueprint". [11]
Low Uric Acid
Multiple sclerosis
Lower serum values of uric acid have been associated with Multiple Sclerosis.[12] Multiple sclerosis (MS) patients have been found to have serum levels ~194µmol/L, with patients in relapse averaging ~160µmol/L and patients in remission averaging ~230µmol/L. Serum uric acid in healthy controls was ~290µmol/L.[13] (1mg/dL=59.48 µmol/L)[14]A 1998 study completed a statistical analysis of 20 million patient records, comparing serum uric acid values in patients with gout and patients with multiple sclerosis. Almost no overlap between the groups was found.[15]
Uric acid has been successfully used in the treatment and prevention of the animal (murine) model of MS. A 2006 study found that elevation of serum uric acid values in multiple sclerosis patients, by oral supplementation with inosine, resulted in lower relapse rates, and no adverse effects.[16]
Oxidative Stress
Uric acid may be a marker of oxidative stress,[17] and may have a potential therapeutic role as an antioxidant (PMID 16375736). On the other hand, like other strong reducing substances such as ascorbate, uric acid can also act as a prooxidant,[18] particularly at elevated levels. Thus, it is unclear whether elevated levels of uric acid in diseases associated with oxidative stress such as stroke and atherosclerosis are a protective response or a primary cause.[19]For example, some researchers propose that hyperuricemia-induced oxidative stress is a cause of Metabolic syndrome.[20][21] On the other hand, plasma uric acid levels correlate with longevity in primates and other mammals.[22] This is presumably a function of urate's antioxidant properties.
Sources of uric acid
In many instances, people have elevated uric acid levels for hereditary reasons.Diet may also be a factor.
Purines are found in high amounts in animal food products, especially internal organs.[23]
Examples of high purine sources include: sweetbreads, anchovies, sardines, liver, beef kidneys, brains, meat extracts (e.g Oxo, Bovril), herring, mackerel, scallops, game meats, and gravy.
A moderate amount of purine is also contained in beef, pork, poultry, fish and seafood, asparagus, cauliflower, spinach, mushrooms, green peas, lentils, dried peas, beans, oatmeal, wheat bran and wheat germ.[24]
Moderate intake of purine-containing food is not associated with an increased risk of gout.[25]
Serum uric acid can be elevated due to high fructose intake, reduced excretion by the kidneys, and or high intake of dietary purine.
Fructose can be found in processed foods and soda beverages - in some countries, in the form of high fructose corn syrup.
Causes of low uric acid
Aside from avoidance of purine foods, both accumulated copper and low vitamin B2 can exacerbate low uric acid levels, which in turn is hypothesized to lead to myelin degeneration seen in Multiple Sclerosis.[26]Other uric acid facts
The high nitrogen content of uric acid makes guano a useful agricultural fertilizer.The crystalline form of uric acid is used as a reflector in certain species of fireflies.
See also
External links
- MedlinePlus - Uric Acid Test
- International Kidney Stone Institute
- Purine content in food
References
1. ^ [1]
2. ^ [2]
3. ^ [3]
4. ^ [4]SI Units for Clinical Data
5. ^ [5]The effect of a vegetarian and different omnivorous diets on urinary risk factors for uric acid stone formation
6. ^ [1]Hyperuricemia and gout: diagnosis and therapy
7. ^ [2]Biochemistry of uric acid and its relation to gout
8. ^ [6]Uric Acid, Serum
9. ^ [7]An amperometric uric acid biosensor based on modified Ir-C electrode
10. ^ [8]Lesch-Nyhan Disease
11. ^ [9]Role of uric acid in hypertension, renal disease, and metabolic syndrome
12. ^ [10]
13. ^ [11]
14. ^ [12]SI Units for Clinical Data
15. ^ [13]Uric acid, a natural scavenger of peroxynitrite, in experimental allergic encephalomyelitis and multiplesclerosis
16. ^ [14]Therapeutic value of serum uric acid levels increasing in the treatment of multiple sclerosis
17. ^ [15]
18. ^ [16]
19. ^ [17]Free Radicals and Human Disease
20. ^ [18] A Causal Role for Uric acid in Fructose-induced Metabolic Syndrome
21. ^ [19]Uric acid: A new look at an old risk marker for cardiovascular disease, metabolic syndrome, and type 2 diabetes mellitus: The urate redox shuttle
22. ^ [20] Urate and ascorbate: their possible roles as antioxidants in determining longevity of mammalian species
23. ^ [21]Gout Causes: List of Diet/Food Sources High or Low in Purine Content
24. ^ [22] Gout Diet / Low Purine Diet - Limit High Purine foods
25. ^ [23]Purine-Rich Foods, Dairy and Protein Intake, and the Risk of Gout in Men
26. ^ [24] The possible role of gradual accumulation of copper, cadmium, lead and iron and gradual depletion of zinc, magnesium, selenium, vitamins B2, B6, D, and E and essential fatty acids in multiple sclerosis
2. ^ [2]
3. ^ [3]
4. ^ [4]SI Units for Clinical Data
5. ^ [5]The effect of a vegetarian and different omnivorous diets on urinary risk factors for uric acid stone formation
6. ^ [1]Hyperuricemia and gout: diagnosis and therapy
7. ^ [2]Biochemistry of uric acid and its relation to gout
8. ^ [6]Uric Acid, Serum
9. ^ [7]An amperometric uric acid biosensor based on modified Ir-C electrode
10. ^ [8]Lesch-Nyhan Disease
11. ^ [9]Role of uric acid in hypertension, renal disease, and metabolic syndrome
12. ^ [10]
13. ^ [11]
14. ^ [12]SI Units for Clinical Data
15. ^ [13]Uric acid, a natural scavenger of peroxynitrite, in experimental allergic encephalomyelitis and multiplesclerosis
16. ^ [14]Therapeutic value of serum uric acid levels increasing in the treatment of multiple sclerosis
17. ^ [15]
18. ^ [16]
19. ^ [17]Free Radicals and Human Disease
20. ^ [18] A Causal Role for Uric acid in Fructose-induced Metabolic Syndrome
21. ^ [19]Uric acid: A new look at an old risk marker for cardiovascular disease, metabolic syndrome, and type 2 diabetes mellitus: The urate redox shuttle
22. ^ [20] Urate and ascorbate: their possible roles as antioxidants in determining longevity of mammalian species
23. ^ [21]Gout Causes: List of Diet/Food Sources High or Low in Purine Content
24. ^ [22] Gout Diet / Low Purine Diet - Limit High Purine foods
25. ^ [23]Purine-Rich Foods, Dairy and Protein Intake, and the Risk of Gout in Men
26. ^ [24] The possible role of gradual accumulation of copper, cadmium, lead and iron and gradual depletion of zinc, magnesium, selenium, vitamins B2, B6, D, and E and essential fatty acids in multiple sclerosis
IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. It is developed and kept up to date under the auspices of the International Union of Pure and Applied Chemistry (IUPAC).
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CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. They are also referred to as CAS numbers, CAS RNs or CAS #s.
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smiles
File extension:
Type of format: chemical file format
The simplified molecular input line entry specification or SMILES
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File extension:
.smiType of format: chemical file format
The simplified molecular input line entry specification or SMILES
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A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. A chemical formula is also a short way of showing how a chemical reaction occurs.
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Molar mass, symbol M,[1] is the mass of one mole of a substance (chemical element or chemical compound).[2] It is a physical property which is characteristic of each pure substance.
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In physics, density is mass m per unit volume V—how heavy something is compared to its size. A small, heavy object, such as a rock or a lump of lead, is denser than a lighter object of the same size or a larger object of the same weight, such as pieces of
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The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. Although the phrase would suggest a specific temperature and is commonly and incorrectly used as such in most textbooks and literature, most crystalline compounds
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boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid.[1][2][3][4]
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Solubility is a physical property referring to the ability for a given substance, the solute, to dissolve in a solvent.[1] It is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. The resulting solution is called a saturated solution.
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Water is a common chemical substance that is essential to all known forms of life.[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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An acid dissociation constant, denoted by Ka, is an equilibrium constant for the dissociation of a weak acid. According to the Brønsted-Lowry theory of acids and bases an acid is only recognised by its reaction with a base.
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standard state of a material is its state at 1 bar (100 kilopascals exactly). This pressure was changed from 1 atm (101.325 kilopascals) by IUPAC in 1990.[1] The standard state of a material can be defined at any given temperature, most commonly 25 degrees Celsius,
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organic compounds]] An organic compound is any member of a large class of chemical compounds whose molecules contain carbon; for historical reasons discussed below, a few types of compounds such as carbonates, carbon oxides and cyanides, as well as elemental carbon are
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4, 2
(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJmol−1
2nd: 2352.6 kJmol−1
3rd: 4620.5 kJmol−1
Atomic radius 70 pm
Atomic radius (calc.
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(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJmol−1
2nd: 2352.6 kJmol−1
3rd: 4620.5 kJmol−1
Atomic radius 70 pm
Atomic radius (calc.
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3, 5, 4, 2
(strongly acidic oxide)
Electronegativity 3.04 (Pauling scale)
Ionization energies
(more) 1st: 1402.3 kJmol−1
2nd: 2856 kJmol−1
3rd: 4578.1 kJmol−1
Atomic radius 65 pm
Atomic radius (calc.
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(strongly acidic oxide)
Electronegativity 3.04 (Pauling scale)
Ionization energies
(more) 1st: 1402.3 kJmol−1
2nd: 2856 kJmol−1
3rd: 4578.1 kJmol−1
Atomic radius 65 pm
Atomic radius (calc.
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2, −1
(neutral oxide)
Electronegativity 3.44 (Pauling scale)
Ionization energies
(more) 1st: 1313.9 kJmol−1
2nd: 3388.3 kJmol−1
3rd: 5300.5 kJmol−1
Atomic radius 60 pm
Atomic radius (calc.
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(neutral oxide)
Electronegativity 3.44 (Pauling scale)
Ionization energies
(more) 1st: 1313.9 kJmol−1
2nd: 3388.3 kJmol−1
3rd: 5300.5 kJmol−1
Atomic radius 60 pm
Atomic radius (calc.
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1, −1
(amphoteric oxide)
Electronegativity 2.20 (Pauling scale) More
Atomic radius 25 pm
Atomic radius (calc.) 53 pm
Covalent radius 37 pm
Van der Waals radius 120 pm
Miscellaneous
Thermal conductivity (300 K) 180.
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(amphoteric oxide)
Electronegativity 2.20 (Pauling scale) More
Atomic radius 25 pm
Atomic radius (calc.) 53 pm
Covalent radius 37 pm
Van der Waals radius 120 pm
Miscellaneous
Thermal conductivity (300 K) 180.
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The enzyme xanthine oxidase, or XO, (bovine milk enzyme is PDB 1FIQ , EC 1.17.3.2 ) catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid
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Reaction
- hypoxanthine + O2 + H2
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Not to be confused with xanthene.
Xanthine (IPA: /ˈzænθiːn, ˈzænθaɪn]/
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Hypoxanthine is a naturally occurring purine derivative.
It is occasionally found as a constituent of nucleic acids where it is present in the anticodon of tRNA in the form of its nucleoside inosine.
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It is occasionally found as a constituent of nucleic acids where it is present in the anticodon of tRNA in the form of its nucleoside inosine.
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Many organisms have metabolic pathways to synthesise and break down purines.
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Synthesis
Purines are biologically synthesized as nucleosides (bases attached to ribose). The committed step is amidophosphoribosyltransferase...... Click the link for more information.
The enzyme urate oxidase, or UO, (Aspergillus flavus enzyme PDB 1R4U , EC 1.7.3.3 ) catalyzes the oxidation of uric acid to 5-hydroxyisourate.
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- Uric acid + O2 + H2O → 5-hydroxyisourate + H2O2
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Allantoin is a chemical compound with formula C4H6N4O3. It is also called 5-ureidohydantoin or glyoxyldiureide. It is a diureide of glyoxylic acid.
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Vitamin C or L -ascorbate is an essential nutrient for higher primates, and a small number of other species. The presence of ascorbate is required for a range of essential metabolic reactions in all animals and in plants and is made internally by almost all organisms,
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A reducing agent (also called a reductant or reducer) is the element or a compound in a redox (reduction-oxidation) reaction (see electrochemistry) that reduces another species.
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An electron donor is a chemical entity that donates electrons to another compound. It is a reducing agent that, by virtue of its donating electrons, is itself oxidized in the process.
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Antioxidant is a molecule capable of slowing or preventing the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons from a substance to an oxidizing agent.
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- For the related metabolic process, see anabolism.
Catabolism is the set of metabolic pathways that break down molecules into smaller units and release energy.
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Aves
Linnaeus, 1758
Orders
About two dozen - see section below
Birds (class Aves) are bipedal, warm-blooded, egg-laying vertebrate animals.
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Linnaeus, 1758
Orders
About two dozen - see section below
Birds (class Aves) are bipedal, warm-blooded, egg-laying vertebrate animals.
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Sauropsida*
Goodrich, 1916
Subclasses
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Goodrich, 1916
Subclasses
- Anapsida
- Diapsida
- Reptilia Laurenti, 1768
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Herod_Archelaus
