A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's role as a catalyst. Cofactors can be considered "helper molecules" that assist in biochemical transformations. The rates at which these happen are characterized in an area of study called enzyme kinetics. Cofactors typically differ from ligands in that they often derive their function by remaining bound.
Methanogens are microorganisms that produce methane as a metabolic byproduct in hypoxic conditions. They belong to the domain Archaea and are members of the phylum Euryarchaeota. Methanogens are common in wetlands, where they are responsible for marsh gas, and can occur in the digestive tracts of animals including ruminants and humans, where they are responsible for the methane content of belching and flatulence. In marine sediments, the biological production of methane, termed methanogenesis, is generally confined to where sulfates are depleted below the top layers and methanogens play an indispensable role in anaerobic wastewater treatments. Other methanogens are extremophiles, found in environments such as hot springs and submarine hydrothermal vents as well as in the "solid" rock of Earth's crust, kilometers below the surface.
Methanogenesis or biomethanation is the formation of methane coupled to energy conservation by microbes known as methanogens. Organisms capable of producing methane for energy conservation have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria. The production of methane is an important and widespread form of microbial metabolism. In anoxic environments, it is the final step in the decomposition of biomass. Methanogenesis is responsible for significant amounts of natural gas accumulations, the remainder being thermogenic.
Tetrahydromethanopterin is a coenzyme in methanogenesis. It is the carrier of the C1 group as it is reduced to the methyl level, before transferring to the coenzyme M.
Coenzyme M is a coenzyme required for methyl-transfer reactions in the metabolism of archaeal methanogens, and in the metabolism of other substrates in bacteria. It is also a necessary cofactor in the metabolic pathway of alkene-oxidizing bacteria. CoM helps eliminate the toxic epoxides formed from the oxidation of alkenes such as propylene. The structure of this coenzyme was discovered by CD Taylor and RS Wolfe in 1974 while they were studying methanogenesis, the process by which carbon dioxide is transformed into methane in some anaerobic bacteria. The coenzyme is an anion with the formula HSCH
2CH
2SO−
3. It is named 2-mercaptoethanesulfonate and abbreviated HS–CoM. The cation is unimportant, but the sodium salt is most available. Mercaptoethanesulfonate contains both a thiol, which is the main site of reactivity, and a sulfonate group, which confers solubility in aqueous media.
Coenzyme B is a coenzyme required for redox reactions in methanogens. The full chemical name of coenzyme B is 7-mercaptoheptanoylthreoninephosphate. The molecule contains a thiol, which is its principal site of reaction.
Methanofurans are a family of chemical compounds found in methanogenic archaea. These species feature a 2-aminomethylfuran linked to phenoxy group. At least three different end groups are recognized: R = tricarboxyheptanoyl (methanofuran), glutamyl-glutamyl, tricarboxy-2-hydroxyheptanoyl.
In enzymology, a tetrahydromethanopterin S-methyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, a 3-methyl-2-oxobutanoate dehydrogenase (ferredoxin) (EC 1.2.7.7) is an enzyme that catalyzes the chemical reaction
In enzymology, a 5,10-methylenetetrahydromethanopterin reductase (EC 1.5.98.2) is an enzyme that catalyzes the chemical reaction
In enzymology, a CoB—CoM heterodisulfide reductase (EC 1.8.98.1) is an enzyme that catalyzes the chemical reaction
Coenzyme F420 is a family of coenzymes involved in redox reactions in a number of bacteria and archaea. It is derived from coenzyme FO (7,8-didemethyl-8-hydroxy-5-deazariboflavin) and differs by having a oligoglutamyl tail attached via a 2-phospho-L-lactate bridge. F420 is so named because it is a flavin derivative with an absorption maximum at 420 nm.
F430 is the cofactor (sometimes called the coenzyme) of the enzyme methyl coenzyme M reductase (MCR). MCR catalyzes the reaction EC 2.8.4.1 that releases methane in the final step of methanogenesis:
(Methyl-Co methanol-specific corrinoid protein):coenzyme M methyltransferase is an enzyme with systematic name methylated methanol-specific corrinoid protein:coenzyme M methyltransferase. This enzyme catalyses the following chemical reaction
Tetramethylammonium-corrinoid protein Co-methyltransferase is an enzyme with systematic name tetramethylammonium:5-hydroxybenzimidazolylcobamide Co-methyltransferase. This enzyme catalyses the following chemical reaction
Methanococcus maripaludis is a species of methanogenic archaea found in marine environments, predominantly salt marshes. M. maripaludis is a weakly motile, non-spore-forming, Gram-negative, strict anaerobic mesophile with a pleomorphic coccoid-rod shape, averaging 1.2 by 1.6 μm is size. The genome of M. maripaludis has been sequenced, and over 1,700 protein-coding genes have been identified. In ideal conditions, M. maripaludis grows quickly and can double every two hours.
3-Nitrooxypropanol, abbreviated 3NOP, is an organic compound with the formula HOCH2CH2CH2ONO2. It is the mononitrate ester of 1,3-propanediol. The compound is an inhibitor of the enzyme methyl coenzyme M reductase (MCR). MCR catalyzes the final step in methanogenesis. When it is fed to ruminants, their methane production is diminished. In 2021 Bovaer, a feed additive for cows produced by DSM based on this compound, has been approved in Brazil, one of the world's largest meat exporters and also Chile. In 2022, it was approved for use on dairy cows in the EU.
C1 chemistry is the chemistry of one-carbon molecules. Although many compounds and ions contain only one carbon, stable and abundant C-1 feedstocks are the focus of research. Four compounds are of major industrial importance: methane, carbon monoxide, carbon dioxide, and methanol. Technologies that interconvert these species are often used massively to match supply to demand.
In enzymology, a formylmethanofuran dehydrogenase (EC 1.2.99.5) is an enzyme that catalyzes the chemical reaction:
Ralph Stoner Wolfe was an American microbiologist, who contributed to the discovery of the single-celled archaea as the third domain of life. He was a pioneer in the biochemistry of methanogenesis.
