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Thiamine pyridinylase
EC number2.5.1.2
CAS number9030-35-7
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum

Thiaminase (EC is an enzyme that metabolizes or breaks down thiamine into two molecular parts.

The old name was "aneurinase".[1]

There are two types:[2]


Source include:


Its physiological role for fish, bacterial cell or insect is not known. However, in ferns it is thought to offer protection from insects[9] 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.[10]

It was first described as the cause of highly mortal ataxic neuropathy in fur producing foxes eating raw entrails of river fish like carp in 1941.

It is also known as the cause of cerebrocortical necrosis of cattle and polioencephalomalasia of sheep eating thiaminase containing plants.[11][12]

It was once causing economical losses in raising fisheries, e.g. in yellowtail fed raw anchovy as a sole feed for a certain period, and also in sea bream and rainbow trout. The same problem is being studied in a natural food chain system.[13]

The larvae of a wild silk worm Anaphe venata are being consumed in a rain forest district of Nigeria as a supplemental protein nutrition, and the heat resistant thiaminase in it is causing an acute seasonal cerebellar ataxia.[14]

In 1860–61, Burke and Wills were the first Europeans to cross Australia south to north; on their return they subsisted primarily on raw nardoo-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.[2]


  1. ^ Fujita A, Nose Y, Kozuka S, et al. (1952). "Studies on thiaminase". J. Biol. Chem. 196 (1): 289–295. PMID 12980969.
  2. ^ a b Thiaminases
  3. ^ NcCleary BV, Chick BF (1977). "The purification and properties of a thiaminaseI from Nardoo (Marsilea drummondii)". Phytochemistry. 16 (2): 207–213. doi:10.1016/S0031-9422(00)86787-4.
  4. ^ Boś M, Kozik A (2000). "Some molecular and enzymatic properties of a homogeneous preparation of thiaminase I purified from carp liver". J Protein Chem. 19 (2): 75–84. doi:10.1023/A:1007043530616. PMID 10945431.
  5. ^ Wittliff JL, Airth RL (1968). "The extracellular thiaminase I of Bacillus thiaminolyticus I. Purification and physicochemical properties". Biochemistry. 7 (2): 736–44. doi:10.1021/bi00842a032. PMID 4966932.
  6. ^ Nakatsuka T, Suzuki K, Nakano Y, Kitaoka S (1988). "Physicochemical properties of intracellular thiaminase II of Bacillus aneurinolyticus". Vitamins (Japan). 62: 15–22.
  7. ^ Toms A, Haas A, Park J, Begley T, Ealick S (2005). "Structural characterization of the regulatory proteins TenA and TenI from Bacillus subtilis and identification of TenA as a thiaminase II". Biochemistry. 44 (7): 2319–29. doi:10.1021/bi0478648. PMID 15709744.
  8. ^ Nishimune T, Watanabe Y, Okazaki H, Akai H (2000). "Thiamin is decomposed due to Anaphe spp. entomophagy in seasonal ataxia patients in Nigeria". J. Nutr. 130: 1625–28.
  9. ^ Vetter. J (2010). "Toxicological and Medicinal Aspects of the Most Frequent Fern Species, Pteridium aquilinum (L.) Kuhn". Working with Ferns: Issues and Applications. pp. 361–375. doi:10.1007/978-1-4419-7162-3_25.
  10. ^ JENKINS, A. H., SCHYNS, G., POTOT, S., SUN, G. & BEGLEY, T. P. (2007). "A new thiamin salvage pathway". Nat Chem Biol. 3: 492–497. doi:10.1038/nchembio.2007.13. PMID 17618314.CS1 maint: Multiple names: authors list (link)
  11. ^ Ramos J, Marca C, Loste A, García de Jalón J, Fernández A, Cubel T (2003). "Biochemical changes in apparently normal sheep from flocks affected by polioencephalomalacia". Vet Res Commun. 27 (2): 111–24. doi:10.1023/A:1022807119539. PMID 12718505.
  12. ^ Evans WC. (1975). "Thiaminases and their effects on animals". Vitamins and Hormones. 33: 467–504. doi:10.1016/S0083-6729(08)60970-X. ISBN 978-0-12-709833-3. PMID 779253.
  13. ^ Fisher JP, Brown SB, Wooster GW, Bowser PR (1998). "Maternal blood, egg and larval thiamin levels correlate with larval survival in landlocked Atlantic salmon". J. Nutr. 128 (12): 2456–66. PMID 9868194.
  14. ^ Adamolekun B, Adamolekun WE, Sonibare AD, Sofowora G (1944). "A double-blind, placebo-controlled study of the efficacy of thiamin hydrochloride in a seasonal ataxia in Nigerians". Neurology. 44 (3 Pt 1): 549–51. doi:10.1212/wnl.44.3_part_1.549. PMID 8145931.

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