Biology:Thiaminase
| Thiamine pyridinylase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 2.5.1.2 | ||||||||
| CAS number | 9030-35-7 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| |||||||||
| Aminopyrimidine aminohydrolase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC number | 3.5.99.2 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / QuickGO | ||||||||
| |||||||||
Thiaminase is an enzyme that metabolizes or breaks down thiamine into pyrimidine and thiazole. It is an antinutrient when consumed.
The old name was "aneurinase".[1]
There are two types with different Enzyme Commission numbers:[2]
- Thiamine pyridinylase, Thiaminase I (EC 2.5.1.2, InterPro: IPR030901)
- Aminopyrimidine aminohydrolase, Thinaminase II (EC 3.5.99.2, InterPro: IPR027574, IPR004305)
- 4-amino-5-aminomethyl-2-methylpyrimidine + H2O <=> 4-amino-5-hydroxymethyl-2-methylpyrimidine + NH2+[5]
- H2O + thiamine <=> 4-amino-5-hydroxymethyl-2-methylpyrimidine + 5-(2-hydroxyethyl)-4-methylthiazole + H+[5]
- Produced by a wide range of plants and bacteria. In these organisms, it is mainly responsible for salvage of thiamine pyrimidine from degradation products, rather than the breakdown of thiamine.[5] In bacteria, it stays inside their cells.[6]
Structure and function
Thiaminase I
Thiaminase I works to cleave the pyrimidine ring in thiamin from the thiazolium ring at the methylene bridge. From there it adds a base compound to the pyrimidine, creating an analogue inhibitor of thiamin. Thiaminase I has the ability to use a multitude of C-N cleaving nucleophilic substrates like cysteine, pyridine, aniline, veratrylamine, dithiothreitol, and quinoline.[7]
When analyzing the structure of Thiaminase I it shows a fold similar to that of group II periplasmic binding proteins like maltose-binding protein.[8] These periplasmic binding proteins have two domains that each contain an α/β fold. These two domains come together to form a deep cleft that are connected by three crossover segments. Due to this structure scientists proposed that Thiaminase I could have evolved from prehistoric periplasmic binding protein that had been responsible for up taking thiamin.[8] Between the two domains, in the cleft, sit the active site for Thiaminase I. Along the cleft there are four acidic residues and six tyrosine residues. In order for Thiamin to interact with Thiaminase I it is positioned in the active site between the pyrimidine and Asp272 by two hydrogen bonds. The Glu241 the goes on to activate the Cys113 to attack C6 of the pyrimidine. This forms a zwitterionic intermediate.[8] The Glu241 causes and protonation and nucleophilic attack that results in the split of the bond between the pyrimidine and the thiazole. When observing the crystalline structure, it has two ⍺/ꞵ-type domains separated by a large cleft. At room temperature the two molecules have a noncrystallographic twofold axis that are bridged by a sulfate ion. [9]
Thiaminase II
Thiaminase II cleaves but does not add a base compound. Thiaminase II can only use water as the nucleophile.[10]
Thiaminase II has been found to be TenA. In order to cleave the C-N bond between the thiazole and pyrimidine Thiaminase only uses water as its nucleophile. When viewing Thiaminase II it is found to have a crystal structure that has 11 helices surrounding a deep acidic pocket.[8] For each monomer present in the quaternary structure it interacts with two other monomers. There are several residues like Tyr112, Phe208, Tyr47, and Tyr163 that have some sort of contribution to the π- stacking environment surrounding the HMP ligand.[8] The Glu205 side chain will form a hydrogen bond with the N1 nitrogen in the pyrimidine ring. Next the Tyr163 and the Asp44 side chain come together to form the hydrogen bonds with the N3 and N4'.[8] Finally the Cys135 catalytic residue is positioned near the C2 in the pyridine ring to complete the split of thiamin into its heterocycles.[8]
Sources
This enzyme can be found in a variety of different sources. It can be found in marine organisms, plants, and bacteria. Since Thiamine (vitamin B1) is a very important substance required for metabolic pathways by almost all organisms, it can be very detrimental to introduce Thiaminase to a system. Frequently an organism gains this enzyme by ingesting another organism that carries it. In most cases, prey fish will contain one of the bacteria that produces this enzyme. When that prey fish is consumed raw without treatment the bacteria will transfer to the consumer.[11] The consumer eventually will fall ill, even die, from a thiamine deficiency. This has been seen in different lab studies. Through these studies the enzyme has been found in zebra fish as well as red cornet fish.[11] Cooking thiaminase-containing foods usually inactivates the enzyme.[11]
Sources of thiaminase I include:
- Plants: Bracken (brake),[12] nardoo,[12] horsetail.[13]
- Fish including zebra fish,[11] carp and goldfish.[14]
- Bacteria such as Paenibacillus thiaminolyticus (formerly in Bacillus),[15] Clostridium sporogenes,[12] C. botulinum.[7]
- An African silk worm, Anaphe venata; this enzyme is more heat-tolerant than other thiaminases and requires a longer cooking time[16]
Sources of thiaminase II include:
- Bacillus aneurinolyticus[6] and Bacillus subtilis.[17]
Effects
Function
It is still unclear what thiaminase does for fish, bacterial cell or insects that contain it. In ferns, thiaminase I is thought to offer protection from insects[18]
Studies have shown that thiamine hydrolase (thiaminase II), 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. Thiamin hydrolysis product N-formyl-4-amino-5-aminomethyl-2-methylpyrimidine is transported into the cell and deformylated by the amidohydrolase ylmB and hydrolyzed to 5-aminoimidazole ribotide.[19]
When ingested
It was first described in 1941 as the cause of highly mortal ataxic neuropathy in fur-producing foxes eating raw entrails of river fish like carp.[citation needed]
It is also known as the cause of cerebrocortical necrosis of cattle and polioencephalomalasia of sheep eating thiaminase containing plants.[20][21]
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.[22]
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 named African seasonal ataxia or Nigerian seasonal ataxia.[23]
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]
References
- ↑ "Studies on thiaminase. I. Activation of thiamine breakdown by organic bases". The Journal of Biological Chemistry 196 (1): 289–95. May 1952. doi:10.1016/S0021-9258(18)55732-X. PMID 12980969.
- ↑ 2.0 2.1 Thiaminases
- ↑ "ENZYME - 2.5.1.2 thiamine pyridinylase". https://enzyme.expasy.org/EC/2.5.1.2.
- ↑ "UniProt P45741". https://www.uniprot.org/uniprotkb/P45741/entry.
- ↑ 5.0 5.1 5.2 "ENZYME - 3.5.99.2 aminopyrimidine aminohydrolase". https://enzyme.expasy.org/EC/3.5.99.2.
- ↑ 6.0 6.1 "Physicochemical properties of intracellular thiaminase II of Bacillus aneurinolyticus". Vitamins (Japan) 62: 15–22. 1988.
- ↑ 7.0 7.1 Sikowitz, MD; Shome, B; Zhang, Y; Begley, TP; Ealick, SE (5 November 2013). "Structure of a Clostridium botulinum C143S thiaminase I/thiamin complex reveals active site architecture .". Biochemistry 52 (44): 7830–9. doi:10.1021/bi400841g. PMID 24079939.
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 Jurgenson, Christopher T.; Begley, Tadhg P.; Ealick, Steven E. (2009). "The Structural and Biochemical Foundations of Thiamin Biosynthesis". Annual Review of Biochemistry 78: 569–603. doi:10.1146/annurev.biochem.78.072407.102340. ISSN 0066-4154. PMID 19348578.
- ↑ Campobasso, Nino; Costello, Colleen A.; Kinsland, Cynthia; Begley, Tadhg P.; Ealick, Steven E. (1998-11-01). "Crystal Structure of Thiaminase-I from Bacillus t hiaminolyticus at 2.0 Å Resolution" (in en). Biochemistry 37 (45): 15981–15989. doi:10.1021/bi981673l. ISSN 0006-2960. PMID 9843405. https://pubs.acs.org/doi/10.1021/bi981673l.
- ↑ "Thiaminase - an overview | ScienceDirect Topics". https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/thiaminase#:~:text=Thiaminase.
- ↑ 11.0 11.1 11.2 11.3 Richter, Catherine A.; Evans, Allison N.; Heppell, Scott A.; Zajicek, James L.; Tillitt, Donald E. (2023-01-13). "Genetic basis of thiaminase I activity in a vertebrate, zebrafish Danio rerio" (in en). Scientific Reports 13 (1): 698. doi:10.1038/s41598-023-27612-5. ISSN 2045-2322. PMID 36639393. Bibcode: 2023NatSR..13..698R.
- ↑ 12.0 12.1 12.2 "The purification and properties of a thiaminase I from Nardoo (Marsilea drummondii)". Phytochemistry 16 (2): 207–213. 1977. doi:10.1016/S0031-9422(00)86787-4. "Thiaminase I enzymes present in the culture solutions of Bacillus thiaminolyticus [3-5] and Clostridium sporogenes [6-8] have been highly purified and detailed kinetic studies performed. But, despite the importance thiaminase I enzyme in stock poisoning by bracken fern [9], there is limited information available on the properties of this or other fern thiaminases.".
- ↑ Fabre B., Geay B., Beaufils P. Thiaminase activity in equisetum arvense and its extracts. Plantes médicinales et phytothérapie. 1993;26(3):190–197.
- ↑ "Some molecular and enzymatic properties of a homogeneous preparation of thiaminase I purified from carp liver". Journal of Protein Chemistry 19 (2): 75–84. February 2000. doi:10.1023/A:1007043530616. PMID 10945431.
- ↑ "The extracellular thiaminase I of Bacillus thiaminolyticus. I. Purification and physicochemical properties". Biochemistry 7 (2): 736–44. February 1968. doi:10.1021/bi00842a032. PMID 4966932.
- ↑ "Thiamin is decomposed due to Anaphe spp. entomophagy in seasonal ataxia patients in Nigeria". J. Nutr. 130 (6): 1625–28. 2000. doi:10.1093/jn/130.6.1625. PMID 10827220. "The thiaminase in the buffer extract of Anaphe pupae was type I".
- ↑ "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. February 2005. doi:10.1021/bi0478648. PMID 15709744.
- ↑ "Toxicological and Medicinal Aspects of the Most Frequent Fern Species, Pteridium aquilinum (L.) Kuhn". Working with Ferns: Issues and Applications. 2010. pp. 361–375. doi:10.1007/978-1-4419-7162-3_25. ISBN 978-1-4419-7161-6.
- ↑ "A new thiamin salvage pathway". Nature Chemical Biology 3 (8): 492–7. August 2007. doi:10.1038/nchembio.2007.13. PMID 17618314.
- ↑ "Biochemical changes in apparently normal sheep from flocks affected by polioencephalomalacia". Veterinary Research Communications 27 (2): 111–24. February 2003. doi:10.1023/A:1022807119539. PMID 12718505.
- ↑ "Thiaminases and their effects on animals". Vitamins and Hormones 33: 467–504. 1975. doi:10.1016/S0083-6729(08)60970-X. ISBN 978-0-12-709833-3. PMID 779253.
- ↑ "Maternal blood, egg and larval thiamin levels correlate with larval survival in landlocked Atlantic salmon". The Journal of Nutrition 128 (12): 2456–66. December 1998. doi:10.1093/jn/128.12.2456. PMID 9868194.
- ↑ "A double-blind, placebo-controlled study of the efficacy of thiamine hydrochloride in a seasonal ataxia in Nigerians". Neurology 44 (3 Pt 1): 549–51. March 1994. doi:10.1212/wnl.44.3_part_1.549. PMID 8145931.
External links
- thiaminase+I at the US National Library of Medicine Medical Subject Headings (MeSH)
- thiaminase+II at the US National Library of Medicine Medical Subject Headings (MeSH)
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