Group:SMART:2010 Pingry SMART Team: Difference between revisions

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== Cofactor specificity ==
== Cofactor specificity ==
==='''Modifying cofactor specificity, 2,5-diketo-d-gluconic acid reductase'''===
==='''Modifying cofactor specificity, 2,5-diketo-d-gluconic acid reductase'''===
2,5 Diketo-D-Gluconic acid reductase is found in corynebacterium and is part of the Aldo Keto Reductase family of enzymes. It exists in two variants: DKGR A and DKGR B; however, due to the higher thermal stability level of DKGR A, it has been chosen for mutation of cofactor specificity. 2,5 DKGR is an important enzyme in the production of vitamin C, one of the most important chemicals manufactured in the world. 2,5 DKGR does this by catalyzing the reduction of 2,5-diketo-D-gluconic acid (2,5 DKG) to 2-Keto-L-gluconic acid (2-KLG); a precursor to vitamin C. It is commercially less expensive to use NADH as a cofactor (as opposed to NADPH) and the catalyzation of 2,5 DKG into 2-KLG as well as being more abundant.
2,5 Diketo-D-gluconic acid reductase (DKGR) is a member of the aldo keto reductase(AKR) family. 2,5-DKGR is found in corynebacterium, the genus classification of soil-dwelling bacteria, and exists in two variants: DKGR A and DKGR B. Both catalyze the reduction of 2,5 diketo-D-gluconic acid to 2Keto-L-gulonic acid, a precursor to L-absorbic acid (Vitamin C), through a series of intermediate chemical steps. Since vitamin C is an essential, main chemical manufactured worldwide, ways to increase efficiency of its production through mutations of cofactor specificity have been studied by Dr. Banta. Significantly, replacing the NADPH cofactor of 2,5-DKGR with NADH has been noted to expedite vitamin C generation because NADH is more stable, commercially less expensive, and more abundant than NADPH. Since DKGR A has a higher thermal stability at 38°C than DKGR B, mutations of amino acids near the cofactor binding site have been made to adapt to the preferable NADH cofactor.


<applet load='1a80' size='400' frame='true' align='left' caption='1a80, 2,5-diketo-d-gluconic acid reductase with NADPH (wild-type)' scene='User:Tommie_Hata/2010_Pingry_S.M.A.R.T._Team/1a80-default/2'/>  
<applet load='1a80' size='400' frame='true' align='left' caption='1a80, 2,5-diketo-d-gluconic acid reductase with NADPH (wild-type)' scene='User:Tommie_Hata/2010_Pingry_S.M.A.R.T._Team/1a80-default/2'/>  
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== Substrate specificity ==
== Substrate specificity ==