Fertilizer Nitrogen Sources, Nitrification of Triazine Nitrogen

Hauck, R. D.; Stephenson, H. F.

doi:10.1021/jf60132a014

Cited by 50 publications

(20 citation statements)

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“…In contrast to the metabolism of atrazine discussed above, the data are consistent with bacteria having evolved the enzymes to liberate ammonia from cyanuric acid long before industrial s-triazine production started 150 years ago (12,21,36,(43)(44)(45)(46)(47)(48)(49)(50)(51). Sequence divergence, broad phylogenetic distribution, and the fixation of the cyanuric acid degradation genes on chromosomes and, in some cases, within operons, all point to an ancient origin of the gene function (29, 52-54).…”

Section: Cyanuric Acid Hydrolase Genes and Enzymessupporting

confidence: 65%

Ancient Evolution and Recent Evolution Converge for the Biodegradation of Cyanuric Acid and Related Triazines

Seffernick

Wackett

2016

Appl Environ Microbiol

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Cyanuric acid was likely present on prebiotic Earth, may have been a component of early genetic materials, and is synthesized industrially today on a scale of more than one hundred million pounds per year in the United States. In light of this, it is not surprising that some bacteria and fungi have a metabolic pathway that sequentially hydrolyzes cyanuric acid and its metabolites to release the nitrogen atoms as ammonia to support growth. The initial reaction that opens the s-triazine ring is catalyzed by the unusual enzyme cyanuric acid hydrolase. This enzyme is in a rare protein family that consists of only cyanuric acid hydrolase (CAH) and barbiturase, with barbiturase participating in pyrimidine catabolism by some actinobacterial species. The X-ray structures of two cyanuric acid hydrolase proteins show that this family has a unique protein fold. Phylogenetic, bioinformatic, enzymological, and genetic studies are consistent with the idea that CAH has an ancient protein fold that was rare in microbial populations but is currently becoming more widespread in microbial populations in the wake of anthropogenic synthesis of cyanuric acid and other s-triazine compounds that are metabolized via a cyanuric acid intermediate. The need for the removal of cyanuric acid from swimming pools and spas, where it is used as a disinfectant stabilizer, can potentially be met using an enzyme filtration system. A stable thermophilic cyanuric acid hydrolase from Moorella thermoacetica is being tested for this purpose. Rings happen. The spontaneous (abiotic) formation of chemicals, especially aromatic rings, is prominent in nature and complements the formation of chemical compounds by biosynthesis (natural products) and human synthesis (anthropogenic products). The most well-known examples of abiotic ring formation are the alicyclic, benzenoid, and polycyclic aromatic hydrocarbon rings found in petroleum that form in the earth's subsurface at high pressure and temperatures of Ͼ200°C (1). In addition to petroleum hydrocarbons, abiotic chemical reactions produce a wide array of oxygen, sulfur, and nitrogen heterocyclic rings.Heterocyclic rings are known to also form spontaneously (1). At 25°C and 1 atm pressure, isocyanic acid spontaneously cyclizes to form a mixture of cyanuric acid and cyamelide (2). Cyamelide is not very stable, but the partially aromatic cyanuric acid ring is highly resistant to abiotic hydrolysis or other ring opening reactions. Given that isocyanic acid is widespread in the universe, where it is commonly found in gas clouds, meteors, and comets (3), the highly stable cyanuric acid is plausibly an important sink of organic carbon, nitrogen, and oxygen in early planetary systems. Recent studies investigating RNA as an early genetic code found that cyanuric acid and triaminopyrimidine self-assemble in water to create aggregates resembling contemporary nucleic acid base pairs. Triaminopyrimidine forms nucleosides with ribose, and upon heating, the cyanuric acid mixture forms gene-length polymers that have been ter...

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Section: Cyanuric Acid Hydrolase Genes and Enzymessupporting

confidence: 65%

Ancient Evolution and Recent Evolution Converge for the Biodegradation of Cyanuric Acid and Related Triazines

Seffernick

Wackett

2016

Appl Environ Microbiol

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“…MEL is also a metabolic byproduct or photo-degradation product of cyromazine, where cyromazine is used as a pesticide for plants [6,7]. MEL has a high nitrogen content (66%), which had been misused as a fertilizer [8]. CYA is commonly used as a component of bleaches in swimming pools [9,10].…”

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confidence: 99%

Gas-phase acid-base properties of melamine and cyanuric acid

Mukherjee

Ren

2010

J. Am. Soc. Mass Spectrom.

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The thermochemical properties of melamine and cyanuric acid were characterized using mass spectrometry measurements along with computational studies. A triple-quadrupole mass spectrometer was employed with the application of the extended Cooks kinetic method. The proton affinity (PA), gas-phase basicity (GB), and protonation entropy (⌬ p S) of melamine were determined to be 226.2 Ϯ 2.0 kcal/mol, 218.4 Ϯ 2.0 kcal/mol, and 26.2 Ϯ 2.0 cal/mol K, respectively. The deprotonation enthalpy (⌬ acid H), gas-phase acidity (⌬ acid G), and deprotonation entropy (⌬ acid S) of cyanuric acid were determined to be 330.7 Ϯ 2.0 kcal/mol, 322.9 Ϯ 2.0 kcal/mol, and 26.1 Ϯ 2.0 cal/mol K, respectively. The geometries and energetics of melamine, cyanuric acid, and related ionic species were calculated at the B3LYP/6-31ϩG(d) level of theory. The computationally predicted proton affinity of melamine (225.9 kcal/mol) and gas-phase deprotonation enthalpy of cyanuric acid (328.4 kcal/mol) agree well with the experimental results. Melamine is best represented as the imide-like triazine-triamine form and the triazine nitrogen is more basic than the amino group nitrogen. Cyanuric acid is best represented as the keto-like tautomer and the N-H group is the most probable proton donor. (J Am Soc Mass Spectrom 2010, 21, 1720 -1729

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“…Melamine first occurred in the food chain during the 1950s and 1960s. The use of melamine as a fertilizer for crops had been envisaged in the early 1950s (Hauck & Stephenson, 1964). Melamine used as non‐protein nitrogen for cattle was described in a patent issued in 1958 (Colby & Mesler, 1958).…”

Section: Why Did People Add Melamine To Milk?mentioning

confidence: 99%

Milk adulteration with melamine in China: crisis and response

Yang

Wei

Zhang

et al. 2009

Quality Assurance and Safety of Crops &Amp; Foods

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Objectives To addresses milk adulteration with melamine in China, and share lessons which both the government and the food industry can draw from this incident. Methods Searching information and data from academic databases, official papers and related websites. Results Melamine's high nitrogen content and its undefined toxicity to humans, encourages people to add it to food to increase the protein content. The adulteration has caused great impacts on the public health and milk industry in China. Conclusion Standardized production and reform of food safety supervision systems are needed to bring a higher degree of food safety in China.

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Fertilizer Nitrogen Sources, Nitrification of Triazine Nitrogen

Cited by 50 publications

References 2 publications

Ancient Evolution and Recent Evolution Converge for the Biodegradation of Cyanuric Acid and Related Triazines

Ancient Evolution and Recent Evolution Converge for the Biodegradation of Cyanuric Acid and Related Triazines

Gas-phase acid-base properties of melamine and cyanuric acid

Milk adulteration with melamine in China: crisis and response

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