Triosephosphate isomerase

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Triosephosphate isomerase 1
Beta-barrel.png

The structure of human TPI PDB 1WYI

Symbol(s): TPI1 TIM
Genetic data
Locus: Chr. 12 p13
Database Links
EC number: 5.3.1.1
Entrez: 7167
OMIM: 190450
RefSeq: NM_000365
UniProt: P60174

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


Overview

Triose-phosphate isomerase (TPI or TIM), is an enzyme (EC 5.3.1.1) that catalyzes the reversible interconversion of the triose phosphate isomers dihydroxyacetone phosphate and D-glyceraldehyde 3-phosphate.

Dihydroxyacetone phosphate triose phosphate isomerase D-glyceraldehyde 3-phosphate
Glycerone-phosphate wpmp.png   D-glyceraldehyde-3-phosphate wpmp.png
Biochem reaction arrow reversible NNNN horiz med.png
 
  triose phosphate isomerase

Compound C00111 at KEGG Pathway Database.Enzyme 5.3.1.1 at KEGG Pathway Database.Compound C00118 at KEGG Pathway Database.

Triose phosphate isomerase (TPI) plays an important role in glycolysis and is essential for efficient energy production. TPI has been found in nearly every organism searched for the enzyme, including animals such as mammals and insects as well as in fungi, plants and bacteria. However, some bacteria that do not perform glycolysis, like ureaplasmas, lack TPI.

In humans, deficiencies in TPI are associated with a progressive, severe neurological disorder called Triose Phosphate Isomerase deficiency.

Triose phosphate isomerase is a massively efficient enzyme, performing the reaction billions of times faster than it would occur naturally in solution. The reaction is so efficient it is limited only by the rate the substrate can diffuse into the enzyme's active site.

Side view of triose phosphate isomerase.

Structure

Triose phosphate isomerase is a dimer of identical subunits, each of which is made up of about 250 amino acid residues. The three-dimensional structure of a subunit contains eight α-helices (blue and red) on the outside and eight parallel β-strands on the inside (violet and yellow). This structural motif is called an αβ-barrel, or a TIM-barrel, and is by far the most commonly observed protein fold. The active site of this enzyme is in the center of the barrel. A glutamic acid residue is involved in the catalytic mechanism. The sequence around the active site residue is conserved in all known triose phosphate isomerases.


See also

References

http://pdbdev.sdsc.edu:48346/pdb/molecules/pdb50_6.html

 v  d  e 
Glycolysis Metabolic Pathway
Glucose Hexokinase Glucose-6-phosphate Phosphoglucoisomerase Fructose 6-phosphate Phosphofructokinase Fructose 1,6-bisphosphate Fructose bisphosphate aldolase Dihydroxyacetone phosphate Glyceraldehyde 3-phosphate Triosephosphate isomerase Glyceraldehyde 3-phosphate Glyceraldehyde phosphate dehydrogenase
D-glucose wpmp.png ATP ADP Alpha-D-glucose-6-phosphate wpmp.png Beta-D-fructose-6-phosphate wpmp.png ATP ADP Beta-D-fructose-1,6-bisphosphate wpmp.png Glycerone-phosphate wpmp.png D-glyceraldehyde-3-phosphate wpmp.png D-glyceraldehyde-3-phosphate wpmp.png NAD+ + Pi NADH + H+
Biochem reaction arrow foward YYNN horiz med.png Biochem reaction arrow reversible NNNN horiz med.png Biochem reaction arrow foward YYNN horiz med.png Biochem reaction arrow reversible NNNN horiz med.png + Biochem reaction arrow reversible NNNN horiz med.png 2 Biochem reaction arrow reversible YYYY horiz med.png
NAD+ + Pi NADH + H+
1,3-Bisphosphoglycerate Phosphoglycerate kinase 3-Phosphoglycerate Phosphoglycerate mutase 2-Phosphoglycerate Enolase Phosphoenolpyruvate Pyruvate kinase Pyruvate Pyruvate dehydrogenase Acetyl-CoA
1,3-bisphospho-D-glycerate wpmp.png ADP ATP 3-phospho-D-glycerate wpmp.png 2-phospho-D-glycerate wpmp.png H2O Phosphoenolpyruvate wpmp.png ADP ATP Pyruvate wpmp.png CoA + NAD+ NADH + H+ + CO2 Acetyl co-A wpmp.png
2 Biochem reaction arrow reversible YYYY horiz med.png 2 Biochem reaction arrow reversible NNNN horiz med.png 2 Biochem reaction arrow reversible NYYN horiz med.png 2 Biochem reaction arrow foward YYNN horiz med.png 2 Biochem reaction arrow foward YYNN horiz med.png 2
ADP ATP H2O

de:Triosephosphatisomerase it:Trioso fosfato isomerasi


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