Triose Phosphate Isomerase Structure & Mechanism: Difference between revisions
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[[Image:TriosePhosphateIsomerase_Ribbon_pastel_photo_small.jpg|thumb|left|240px|Ribbon drawing for one subunit of the "TIM barrel" fold]] | |||
===General Information=== | ===General Information=== | ||
Triose phosphate isomerase (TIM)<ref>PMID:16511037</ref><ref>PMID:8061610</ref> (PDB [[1wyi]] and [[1hti]]) is a crucial enzyme in the glycolytic pathway. <scene name='Christian_Krenk_Sandbox/Nc_rainbow/1'>TIM</scene> reversibly converts the aldose Glyceraldehyde-3-phosphate (GAP) to the ketose Dihydroxyacetone phosphate (DHAP). The interconversion proceeds by an enediol intermediate. Triose phosphate isomerase is not directly regulated, but the enzyme two steps before it in the glycolytic pathway, phosphofructokinase, is a heavily regulated, irreversible enzyme. | Triose phosphate isomerase (TIM)<ref>PMID:16511037</ref><ref>PMID:8061610</ref> (PDB [[1wyi]] and [[1hti]]) is a crucial enzyme in the glycolytic pathway. <scene name='Christian_Krenk_Sandbox/Nc_rainbow/1'>TIM</scene> reversibly converts the aldose Glyceraldehyde-3-phosphate (GAP) to the ketose Dihydroxyacetone phosphate (DHAP). The interconversion proceeds by an enediol intermediate. Triose phosphate isomerase is not directly regulated, but the enzyme two steps before it in the glycolytic pathway, phosphofructokinase, is a heavily regulated, irreversible enzyme. | ||
===Structural Characteristics=== | ===Structural Characteristics=== | ||
The secondary structure consists of 14 alpha helices and 8 beta sheets per monomer, making it fall in the SCOP category of alpha and beta proteins. The tertiary structure is a <scene name='Christian_Krenk_Sandbox/Alpha_beta_barrel/2'>alpha-beta barrel | The secondary structure consists of 14 alpha helices and 8 beta sheets per monomer, making it fall in the SCOP category of alpha and beta proteins. The tertiary structure is a <scene name='Christian_Krenk_Sandbox/Alpha_beta_barrel/2'>alpha-beta barrel</scene>, and it is the prototypical example of the "TIM barrel" fold (see ribbon drawing). | ||
The quaternary structure is a homodimer. The molecular weight of the enzyme is estimated at 57,400 Da.<ref name= "dab">PMID:752201</ref> | The quaternary structure is a homodimer. The molecular weight of the enzyme is estimated at 57,400 Da.<ref name= "dab">PMID:752201</ref> | ||