InterPro domain: IPR000652

Triosephosphate isomerase ( 5.3.1.1 ) (TIM) [ 1 ] is the glycolytic enzyme that catalyses the reversible interconversion of glyceraldehyde 3-phosphate and dihydroxyacetone phosphate. TIM plays an important role in several metabolic pathways and is essential for efficient energy production. It is present ineukaryotes as well as in prokaryotes.TIM is a dimer of identical subunits, each of which is made up of about 250 amino-acid residues. A glutamic acid residue is involved in the catalytic mechanism [ 2 , 3 ].

The tertiary structure of TIM has eight beta/alpha motifs folded into a barrel structure. The TIM barrel fold occurs ubiquitously and is found in numerous other enzymes that can be involved in energy metabolism, macromolecule metabolism, or small molecule metabolism [ 4 ].

The sequence around the active site residue is perfectly conserved in all known TIM's. Deficiencies in TIM are associated with haemolytic anaemia coupled with a progressive, severe neurological disorder [ 5 ].

1. Structure of yeast triosephosphate isomerase at 1.9-A resolution. Biochemistry 29, 6609-18
2. Enzyme catalysis: not different, just better. Nature 350, 121-4
3. Optimal alignment for enzymatic proton transfer: structure of the Michaelis complex of triosephosphate isomerase at 1.2-A resolution. Proc. Natl. Acad. Sci. U.S.A. 100, 50-5
4. One fold with many functions: the evolutionary relationships between TIM barrel families based on their sequences, structures and functions. J. Mol. Biol. 321, 741-65
5. Triosephosphate isomerase deficiency: a neurodegenerative misfolding disease. Biochem. Soc. Trans. 30, 30-8