25245-58-3Relevant articles and documents
-
Unrau,A.M.
, p. 1741 - 1745 (1964)
-
DXP reductoisomerase: Reaction of the substrate in pieces reveals a catalytic role for the nonreacting phosphodianion group
Kholodar, Svetlana A.,Murkin, Andrew S.
, p. 2302 - 2308 (2013)
The role of the nonreacting phosphodianion group of 1-deoxy-d-xylulose-5- phosphate (DXP) in catalysis by DXP reductoisomerase (DXR) was investigated for the reaction of the substrate in pieces . The truncated substrate 1-deoxy-l-erythrulose is converted by DXR to 2-C-methylglycerol with a k cat/Km that is 106-fold lower than that for DXP. Phosphite dianion was found to be a nonessential activator, providing 3.2 kcal/mol of transition state stabilization for the truncated substrate. These results implicate a phosphate-driven conformational change involving loop closure over the DXR active site to generate an environment poised for catalysis.
The role of phosphate in a multistep enzymatic reaction: Reactions of the substrate and intermediate in pieces
Kholodar, Svetlana A.,Allen, C. Leigh,Gulick, Andrew M.,Murkin, Andrew S.
, p. 2748 - 2756 (2015/03/04)
Several mechanistically unrelated enzymes utilize the binding energy of their substrate's nonreacting phosphoryl group to accelerate catalysis. Evidence for the involvement of the phosphodianion in transition state formation has come from reactions of the substrate in pieces, in which reaction of a truncated substrate lacking its phosphorylmethyl group is activated by inorganic phosphite. What has remained unknown until now is how the phosphodianion group influences the reaction energetics at different points along the reaction coordinate. 1-Deoxy-d-xylulose-5-phosphate (DXP) reductoisomerase (DXR), which catalyzes the isomerization of DXP to 2-C-methyl-d-erythrose 4-phosphate (MEsP) and subsequent NADPH-dependent reduction, presents a unique opportunity to address this concern. Previously, we have reported the effect of covalently linked phosphate on the energetics of DXP turnover. Through the use of chemically synthesized MEsP and its phosphate-truncated analogue, 2-C-methyl-d-glyceraldehyde, the current study revealed a loss of 6.1 kcal/mol of kinetic barrier stabilization upon truncation, of which 4.4 kcal/mol was regained in the presence of phosphite dianion. The activating effect of phosphite was accompanied by apparent tightening of its interactions within the active site at the intermediate stage of the reaction, suggesting a role of the phosphodianion in disfavoring intermediate release and in modulation of the on-enzyme isomerization equilibrium. The results of kinetic isotope effect and structural studies indicate rate limitation by physical steps when the covalent linkage is severed. These striking differences in the energetics of the natural reaction and the reactions in pieces provide a deeper insight into the contribution of enzyme-phosphodianion interactions to the reaction coordinate.
Development of a multikilogram synthesis of a chiral epoxide precursor to a CCR1 antagonist. Use of in situ monitoring for informed optimisation via fragile intermediates
Ange, Debra,Booker, James E. M.,Pedge, Nicholas,Sinclair, Rhona,Sleigh, Chris,Stefinovic, Marijan,Vaz, Luis-Manuel,Way, Edward
experimental part, p. 72 - 84 (2010/05/02)
The optimisation and scale up of a manufacturing route to a key intermediate, acetic acid 4-acetylamino-3-(2-methyl-oxiranyl- methoxy)phenyl ester (2), utilising a SNAr coupling, the hydro- genation of a nitro moiety and the conversion of a chi
