1 Contains
| DB identifier | Name | Short Name | Type |
|---|---|---|---|
| IPR020826 | Transketolase binding site | Transketolase_BS | Binding_site |
| Name | Transketolase-like, pyrimidine-binding domain | Short Name | Transketolase-like_Pyr-bd |
| Type | Domain | Description | Transketolase (TK) catalyzes the reversible transfer of atwo-carbon ketol unit from xylulose 5-phosphate to an aldose receptor, such asribose 5-phosphate, to form sedoheptulose 7-phosphate and glyceraldehyde 3-phosphate. This enzyme, together with transaldolase, provides a link betweenthe glycolytic and pentose-phosphate pathways.TK requires thiamine pyrophosphate as a cofactor. In most sources where TK hasbeen purified, it is a homodimer of approximately 70 Kd subunits. TK sequencesfrom a variety of eukaryotic and prokaryotic sources [, ]show that theenzyme has been evolutionarily conserved.In the peroxisomes of methylotrophic yeast Pichia angusta(Yeast) (Hansenula polymorpha), there is ahighly related enzyme, dihydroxy-acetone synthase (DHAS) (alsoknown as formaldehyde transketolase), which exhibits a very unusualspecificity by including formaldehyde amongst its substrates.1-deoxyxylulose-5-phosphate synthase (DXP synthase) []is an enzyme so farfound in bacteria (gene dxs) and plants (gene CLA1) which catalyzes thethiamine pyrophosphoate-dependent acyloin condensation reaction between carbonatoms 2 and 3 of pyruvate and glyceraldehyde 3-phosphate to yield 1-deoxy-D-xylulose-5-phosphate (dxp), a precursor in the biosynthetic pathway toisoprenoids, thiamine (vitamin B1), and pyridoxol (vitamin B6). DXP synthaseis evolutionary related to TK. The N-terminal section, contains a histidine residue which appears to function inproton transfer during catalysis []. In the centralsection there are conserved acidic residues that are part of the active cleftand may participate in substrate-binding [].This family includes transketolase enzymes and also partially matches to 2-oxoisovalerate dehydrogenasebeta subunit . Both these enzymesutilise thiamine pyrophosphate as a cofactor, suggestingthere may be common aspects in their mechanism of catalysis. |
| DB identifier | Name | Short Name | Type |
|---|---|---|---|
| IPR020826 | Transketolase binding site | Transketolase_BS | Binding_site |
