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| | Nestor is the title my parents gave me but I don't like when people use my full name. Managing individuals is what I do in my day job. I currently reside in Alabama. Playing crochet is some thing that I've carried out for years.<br><br>Feel free to visit my webpage - [http://zocken-in-Gesellschaft.de/index.php?mod=users&action=view&id=10093 car warranty companies] |
| {{enzyme
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| | Name = Transaldolase
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| | EC_number = 2.2.1.2
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| | CAS_number = 9014-46-4
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| | IUBMB_EC_number = 2/2/1/2
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| | GO_code = 0004801
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| | image =
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| | width =
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| | caption =
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| }}
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| {{Pfam_box
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| | Symbol = Transaldolase
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| | Name = Transaldolase
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| | image = Transaldolaseribbon.jpg
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| | width =
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| | caption = Crystallographic structure of human transaldolase.<ref name="pmid10869557"/><ref name="pmid15264254">Molecular graphics images were produced using the UCSF Chimera package from the Resource for Biocomputing, Visualization, and Informatics at the University of California, San Francisco. {{cite journal | author = Pettersen EF, Goddard TD, Huang CC, Couch GS, Greenblatt DM, Meng EC, Ferrin TE | title = UCSF Chimera–a visualization system for exploratory research and analysis | journal = J Comput Chem | volume = 25 | issue = 13 | pages = 1605–12 |date=October 2004 | pmid = 15264254 | doi = 10.1002/jcc.20084 | url = | issn = }}</ref>
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| | Pfam = PF00923
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| | InterPro = IPR001585
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| | SMART=
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| | PROSITE = PDOC00741
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| | SCOP = 1ucw
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| | TCDB =
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| | OPM family =
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| | OPM protein =
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| | PDB = {{PDB2|1f05}}, {{PDB2|1i2n}}, {{PDB2|1i2o}}, {{PDB2|1i2p}}, {{PDB2|1i2q}}, {{PDB2|1i2r}}, {{PDB2|1l6w}}, {{PDB2|1onr}}, {{PDB2|1ucw}},{{PDB2|1vpx}}, {{PDB2|2cwn}}
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| }}
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| {{protein
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| | name = transaldolase 1
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| | caption =
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| | image =
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| | width =
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| | HGNCid = 11559
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| | Symbol = TALDO1
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| | AltSymbols =
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| | EntrezGene = 6888
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| | OMIM = 602063
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| | RefSeq = NM_006755
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| | UniProt = P37837
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| | PDB =
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| | ECnumber = 2.2.1.2
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| | Chromosome = 11
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| | Arm = p
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| | Band = 15.5-15.4
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| | LocusSupplementaryData =
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| }}
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| {{protein
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| |Name=transaldolase B
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| |caption=
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| |image=
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| |width=
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| |Symbol=talB
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| |AltSymbols=
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| |EntrezGene=4199095
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| |RefSeq=NC_008245.1
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| |UniProt=P0A870
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| |PDB=1onr
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| |ECnumber=2.2.1.2
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| |Chromosome=
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| |Arm=p
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| |Band=15.5?
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| |LocusSupplementaryData=-15.4?
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| }}
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| {{stack end}}
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| '''Transaldolase''' is an [[enzyme]] ({{EC number|2.2.1.2}}) of the non-oxidative phase of the [[pentose phosphate pathway]]. In humans, transaldolase is encoded by the ''TALDO1'' [[gene]].<ref name="entrez">{{cite web | title = Entrez Gene: transaldolase 1| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=6888 | accessdate = }}</ref><ref name="pmid9339383">{{cite journal | author = Banki K, Eddy RL, Shows TB, Halladay DL, Bullrich F, Croce CM, Jurecic V, Baldini A, Perl A | title = The human transaldolase gene (TALDO1) is located on chromosome 11 at p15.4-p15.5 | journal = Genomics | volume = 45 | issue = 1 | pages = 233–8 |date=October 1997 | pmid = 9339383 | doi = 10.1006/geno.1997.4932 | url = | issn = }}</ref>
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| The following chemical reaction is catalyzed by transaldolase:
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| * [[sedoheptulose 7-phosphate]] + [[glyceraldehyde 3-phosphate]] <math>\rightleftharpoons</math> [[erythrose 4-phosphate]] + [[fructose 6-phosphate]]
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| ==Clinical significance==
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| The pentose phosphate pathway has two metabolic functions: (1) generation of nicotinamide adenine dinucleotide phosphate (reduced [[nicotinamide adenine dinucleotide phosphate|NADPH]]), for reductive biosynthesis, and (2) formation of [[ribose]], which is an essential component of [[Adenosine triphosphate|ATP]], [[DNA]], and [[RNA]]. Transaldolase links the pentose phosphate pathway to [[glycolysis]]. In patients with deficiency of transaldolase, there's an accumulation of [[erythritol]] (from [[erythrose 4-phosphate]]), D-[[arabitol]], and [[ribitol]].<ref name="pmid11283793"/><ref name="pmid17613166">{{cite journal | author = Perl A | title = The pathogenesis of transaldolase deficiency | journal = IUBMB Life | volume = 59 | issue = 6 | pages = 365–73 |date=June 2007 | pmid = 17613166 | doi = 10.1080/15216540701387188 | url = | issn = }}</ref>
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| The deletion in 3 base pairs in the ''TALDO1'' gene results in the absence of serine at position 171 of the transaldolase protein, which is part of a highly conserved region, suggesting that the mutation causes the transaldolase deficiency that is found in [[erythrocyte]]s and [[lymphoblast]]s.<ref name="pmid11283793">{{cite journal | author = Verhoeven NM, Huck JH, Roos B, Struys EA, Salomons GS, Douwes AC, van der Knaap MS, Jakobs C | title = Transaldolase deficiency: liver cirrhosis associated with a new inborn error in the pentose phosphate pathway | journal = Am. J. Hum. Genet. | volume = 68 |issue = 5 | pages = 1086–92 |date=May 2001 | pmid = 11283793 | pmc = 1226089 | doi = 10.1086/320108 | url = | issn = }}</ref> The deletion of this amino acid can lead to [[liver cirrhosis]] and [[hepatosplenomegaly]] (enlarged spleen and liver) during early infancy. Transaldolase is also a target of [[autoimmunity]] in patients with [[multiple sclerosis]].<ref name="pmid15286385">{{cite journal
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| |author = Niland B, Perl A | title = Evaluation of autoimmunity to transaldolase in multiple sclerosis | journal = Methods Mol. Med. | volume = 102 | issue = | pages = 155–71 | year = 2004 | pmid = 15286385 | doi = 10.1385/1-59259-805-6:155 | url = | issn = }}</ref>
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| ==Structure==
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| [[Image:Transaldolase Active Site.jpg|thumb|left|300px|Active site of the transaldolase enzyme highlighting the key amino acid residues (Asp-27, Glu-106, and Lys-142) involved in catalysis.<ref name="pmid10869557"/>]]
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| Transaldolase is a single domain composed of 337 amino acids. The core structure is an [[Α/β proteins|α/β barrel]], similar to other class I aldolases, made up of eight parallel [[beta sheet|β-sheets]] and seven [[alpha helix|α-helices]]. There are also seven additional α-helices that are not part of the barrel. Hydrophobic amino acids are located between the β-sheets in the barrel and the surrounding α-helices to contribute to packing, such as the area containing Leu-168, Phe-170, Phe-189, Gly-311, and Phe-315. In the crystal, human transaldolase forms a dimer, with the two subunits connected by 18 residues in each subunit. See mechanism to the left for details.
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| The active site, located in the center of the barrel, contains three key residues: lysine-142, glutamate-106, and aspartate-27. The lysine holds the sugar in place while the glutamate and aspartate act as proton donors and acceptors.<ref name="pmid10869557">{{PDB|1F05}}; {{cite journal | author = Thorell S, Gergely P, Banki K, Perl A, Schneider G |title = The three-dimensional structure of human transaldolase | journal = FEBS Lett. | volume = 475 | issue = 3 | pages = 205–8 |date=June 2000 | pmid = 10869557 | doi = 10.1016/S0014-5793(00)01658-6 | url = | issn = }}</ref>
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| {{-}}
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| ==Mechanism of catalysis==
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| The residue of lysine-142 in the active site of transaldolase forms a [[Schiff base]] with the keto group in [[sedoheptulose-7-phosphate]] after deprotonation by another active site residue, glutamate-106. The reaction mechanism is similar to the reverse reaction catalyzed by [[aldolase]]: The bond joining carbons 3 and 4 is broken, leaving [[dihydroxyacetone]] joined to the enzyme via a Schiff base. This cleavage reaction generates the unusual aldose sugar [[erythrose-4-phosphate]]. Then transaldolase catalyzes the condensation of [[glyceraldehyde-3-phosphate]] with the Schiff base of [[dihydroxyacetone]], yielding enzyme-bound [[fructose 6-phosphate]]. Hydrolysis of the Schiff base liberates free [[fructose 6-phosphate]], one of the products of the pentose phosphate pathway.
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| {{Gallery
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| |title=
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| |width=400
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| |lines=2
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| |Image:transaldolasemech.jpg|Reaction scheme for the conversion of sedoheptulose-7-phosphate to fructose-6-phosphate.<ref name="pmid9007983">{{cite journal | author = Jia J, Schörken U, Lindqvist Y, Sprenger GA, Schneider G | title = Crystal structure of the reduced Schiff-base intermediate complex of transaldolase B from Escherichia coli: mechanistic implications for class I aldolases | journal = Protein Sci. | volume = 6 | issue = 1 | pages = 119–24 |date=January 1997 | pmid = 9007983 | pmc = 2143518 | doi = 10.1002/pro.5560060113| url = http://www.proteinscience.org/cgi/content/abstract/6/1/119 | issn = }}</ref>
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| |Image:transaldolaserepofppp.jpg|The pentose phosphate pathway adapted from (Verhoeven, 2001)<ref name="pmid11283793" />
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| }}
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| ==See also==
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| * [[Transaldolase deficiency]]
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| ==References==
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| {{reflist}}
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| ==External links== | |
| * {{MeshName|Transaldolase}}
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| {{Aldehyde-ketone transferases}}
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| {{Pentose phosphate pathway}}
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| [[Category:EC 2.2.1]]
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Nestor is the title my parents gave me but I don't like when people use my full name. Managing individuals is what I do in my day job. I currently reside in Alabama. Playing crochet is some thing that I've carried out for years.
Feel free to visit my webpage - car warranty companies