Wildtype and Engineered Monomeric Triosephosphate Isomerase from <i>Trypanosoma brucei</i>: Partitioning of Reaction Intermediates in D<sub>2</sub>O and Activation by Phosphite Dianion
作者:M. Merced Malabanan、Maybelle K. Go、Tina L. Amyes、John P. Richard
DOI:10.1021/bi2005416
日期:2011.6.28
ratio of the yields of d-DHAP and d-GAP for wildtype TIM from muscle sources and Trypanosoma brucei brucei, but partitioning of the enediolate intermediate of the monoTIM reaction to form d-DHAP is less favorable ((kC1)D/(kC2)D = 1.1) than for the wildtype enzyme ((kC1)D/(kC2)D = 1.7). Product yields for the wildtype Tbb TIM and monoTIM-catalyzed reactions of glycolaldehyde labeled with carbon-13 at the
确定了由来自布氏锥虫的野生型磷酸丙糖异构酶( Tbb TIM) 和这种野生型酶的单体变体 (monoTIM)催化的 ( R )-3-磷酸甘油醛 (GAP) 在 D 2 O 中在 pD 7.9 中反应的产物产率通过1 H NMR 光谱,并与早期工作中确定的产率进行了比较,这些反应由来自兔和鸡肌肉的 TIM 催化反应[O'Donoghue,AC,Amyes,TL 和 Richard,JP( 2005 ) ,生物化学44 , 2610−2621]。从 TIM 催化的反应中观察到三种产物:磷酸二羟丙酮 (DHAP) 来自氢分子内转移的异构化,d- DHAP 来自异构化,将 D 2 O 中的氘掺入到 DHAP 的 C-1 中,d- GAP 来自掺入将氘从 D 2 O 转化为 GAP 的 C-2。通过氢的分子内转移形成的 DHAP 的产率从肌肉酶的 49% 下降到野生型Tbb TIM 的40% 到monoTIM