Thiaminase is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

that

metabolizes Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

or breaks down

thiamine Thiamine, also known as thiamin and vitamin B1, is a vitamin, an essential micronutrient, that cannot be made in the body. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosphorylated forms of thi ...

into two molecular parts. It is an antinutrient when consumed. The old name was "aneurinase". There are two types:Thiaminases
/ref> * Thiamine pyridinylase, Thiaminase I (, ) * Aminopyrimidine aminohydrolase, Thinaminase II (, , )

Sources

Source include: *

Bracken Bracken (''Pteridium'') is a genus of large, coarse ferns in the family Dennstaedtiaceae. Ferns (Pteridophyta) are vascular plants that have alternating generations, large plants that produce spores and small plants that produce sex cells (eggs ...

(brake),

nardoo ''Marsilea drummondii'' is a species of fern known by the common name nardoo. It is native to Australia, where it is widespread and common, particularly in inland regions. It is a rhizome, rhizomatous perennial aquatic plant, aquatic fern that ro ...

, horsetail, and other plants. * Some

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

including

carp Carp are various species of oily freshwater fish from the family Cyprinidae, a very large group of fish native to Europe and Asia. While carp is consumed in many parts of the world, they are generally considered an invasive species in parts of ...

and goldfish. * A few strains of bacteria such as '' Paenibacillus thiaminolyticus'' (''Bacillus thiaminolyticus''), '' Bacillus aneurinolyticus'', or '' Bacillus subtilis''. * An African silk worm, ''

Anaphe venata ''Anaphe venata'' is a moth of the family Notodontidae. It was described by Arthur Gardiner Butler in 1878. It lives in Angola, Cameroon, the Central African Republic, the Republic of the Congo, the Democratic Republic of the Congo, Equatorial Gui ...

Effects

Its physiological role for fish, bacterial cell or insect is not known. However, in ferns it is thought to offer protection from insects while studies have shown that thiamine hydrolase (thiaminase type 2) which was originally thought to be involved solely in the degradation of thiamine has actually been identified as having a role in thiamine degradation with the salvage of the pyrimidine moiety where thiamin hydrolysis product N-formyl-4-amino-5-aminomethyl-2-methylpyrimidine is transported into the cell and deformylated by the ylmB-encoded amidohydrolase and hydrolyzed to 5-aminoimidazole ribotide. It was first described in 1941 as the cause of highly mortal

ataxic Ataxia is a neurological sign consisting of lack of voluntary Motor coordination, coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicati ...

neuropathy Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or o ...

fur Fur is a thick growth of hair that covers the skin of mammals. It consists of a combination of oily guard hair on top and thick underfur beneath. The guard hair keeps moisture from reaching the skin; the underfur acts as an insulating blanket t ...

-producing foxes eating raw entrails of river fish like carp. It is also known as the cause of cerebrocortical necrosis of

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...

and

polioencephalomalasia Polioencephalomalacia (PEM), also referred to as cerebrocortical necrosis (CCN), is a neurological disease seen in ruminants that is caused by multiple factors, one of which is thiamine depletion in the body. Thiamine (vitamin B1) is a key chemic ...

sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated s ...

eating thiaminase containing plants. It was once causing economical losses in raising

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...

, e.g. in yellowtail fed raw anchovy as a sole feed for a certain period, and also in

sea bream The Sparidae are a family of fish in the order Perciformes, commonly called sea breams and porgies. The sheepshead, scup, and red seabream are species in this family. Most sparids are deep-bodied compressed fish with a small mouth separated by a ...

and

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coasta ...

. The same problem is being studied in a natural food chain system. The larvae of a wild silk worm ''Anaphe venata'' are being consumed in a rain forest district of

Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...

as a supplemental protein nutrition, and the heat-resistant thiaminase in it is causing an acute seasonal

cerebellar ataxia Cerebellar ataxia is a form of ataxia originating in the cerebellum. Non-progressive congenital ataxia (NPCA) is a classical presentation of cerebral ataxias. Cerebellar ataxia can occur as a result of many diseases and may present with symptoms ...

named

African seasonal ataxia ''Anaphe venata'' is a moth of the family Notodontidae. It was described by Arthur Gardiner Butler in 1878. It lives in Angola, Cameroon, the Central African Republic, the Republic of the Congo, the Democratic Republic of the Congo, Equatorial G ...

Nigerian seasonal ataxia ''Anaphe venata'' is a moth of the family Notodontidae. It was described by Arthur Gardiner Butler in 1878. It lives in Angola, Cameroon, the Central African Republic, the Republic of the Congo, the Democratic Republic of the Congo, Equatorial G ...

. In 1860–61, Burke and Wills were the first Europeans to cross

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

south to north; on their return they subsisted primarily on raw

-fern. It is possible that this led to their death due to the extremely high levels of thiaminase contained in nardoo. The Aborigines prepared nardoo by soaking the sporocarps in water for at least a day to avoid the effects of thiamine deficiency that would result from ingesting the leaves raw. In the explorers' journals they noted many symptoms of thiamine deficiency, so it is thought that they did not soak the nardoo long enough. Eventually thiamine deficiency could have led to their demise. It is noteworthy to mention that there are several other hypotheses regarding what may have killed Burke and Wills and it is widely disagreed upon by historians and scientists alike.

References

External links

* * {{Portal bar, Biology, border=no EC 2.5.1