dichloride anion radical with nucleosides, nucleotides, and polynucleotides were determined in neutral aqueoussolutions of potassium chloride by the conventional flashphotolysis. The reactivities of these compounds toward the anion radical are in the order: bases>nucleosides>nucleotides>polynucleotides. This trend is similar to that observed with the corresponding reactions with hydroxyl radical. A comparison
Transition State Analysis of Acid-Catalyzed dAMP Hydrolysis
作者:Joe A. B. McCann、Paul J. Berti
DOI:10.1021/ja067371l
日期:2007.6.6
Multiple kinetic isotope effects (KIEs) on deoxyadenosine monophosphate (dAMP) hydrolysis in 0.1 M HCl were used to determine the transitionstate (TS) structure and probe its intrinsic reactivity. The experimental KIEs revealed a stepwise (SN1) mechanism, with a discrete oxacarbenium ion intermediate. This is the first direct evidence for the deoxyribosyl oxacarbenium ion in solution. In 50% methanol/0
Efficient Production of 2-Deoxyribose 5-Phosphate from Glucose and Acetaldehyde by Coupling of the Alcoholic Fermentation System of Baker’s Yeast and Deoxyriboaldolase-Expressing<i>Escherichia coli</i>
of AMP, and the reaction supernatant containing the fructose 1,6-diphosphate was used directly as substrate for 2-deoxyribose 5-phosphate production with the E. coli cells. With 178 mM enzymatically prepared fructose 1,6-diphosphate and 400 mM acetaldehyde as substrates, 246 mM (52.6 g/l) 2-deoxyribose 5-phosphate was produced. The molar yield of 2-deoxyribose 5-phosphate as to glucose through the total
Deoxyribose 5-phosphate aldolase as a catalyst in asymmetric aldol condensation
作者:Lihren Chen、David P. Dumas、Chi Huey Wong
DOI:10.1021/ja00028a050
日期:1992.1
This paper describes the substrate specificity and synthetic utility of deoxyribose-5-phosphate aldolase (DERA, EC 4.1.2.4). Eight donors and 20 acceptors have been tested as substrates. In addition to acetaldehyde, propanal, acetone, and fluoroacetone have been used to condense with a number of acceptor aldehydes. Thirteen aldol products have been prepared and characterized. A new stereogenic center with 3(S) configuration is formed when acetaldehyde, fluoroacetone, or acetone is used as a donor substrate. With propanal, two new stereogenic centers are formed with 2(R) and 3(S) configurations. The acceptor substrates have very little structural requirements. The 2-hydroxyaldehydes appear to react the fastest, and the D-isomers are better substrates than the L-isomers. The stereospecificity is absolute regardless of the chirality of 2-hydroxyaldehydes. The aldol reactions thus follow the Cram-Felkin mode of attack for D-substrates and anti-Cram-Felkin mode of attack for L-substrates.
Schuchmann, Heinz-Peter; Wagner, Rita; Sonntag, Clemens von, Zeitschrift fur Naturforschung, Teil B: Anorganische Chemie, Organische Chemie, 1983, vol. 38, # 10, p. 1213 - 1220
作者:Schuchmann, Heinz-Peter、Wagner, Rita、Sonntag, Clemens von