1122-95-8Relevant articles and documents
Do electrostatic interactions with positively charged active site groups tighten the transition state for enzymatic phosphoryl transfer?
Nikolic-Hughes, Ivana,Rees, Douglas C.,Herschlag, Daniel
, p. 11814 - 11819 (2004)
The effect of electrostatic interactions on the transition-state character for enzymatic phosphoryl transfer has been a subject of much debate. In this work, we investigate the transition state for alkaline phosphatase (AP) using linear free-energy relationships (LFERs). We determined fcat/K M for a series of aryl sulfate ester monoanions to obtain the Bronsted coefficient, βIg, and compared the value to that obtained previously for a series of aryl phosphorothioate ester dianion substrates. Despite the difference in substrate charge, the observed Bronsted coefficients for AP-catalyzed aryl sulfate and aryl phosphorothioate hydrolysis (-0.76 ± 0.14 and -0.77 ± 0.10, respectively) are strikingly similar, with steric effects being responsible for the uncertainties in these values. Aryl sulfates and aryl phosphates react via similar loose transition states in solution. These observations suggest an apparent equivalency of the transition states for phosphorothioate and sulfate hydrolysis reactions at the AP active site and, thus, negligible effects of active site electrostatic interactions on charge distribution in the transition state.
Bivalent tin(II)-4-methoxyphenoxide: synthesis, characterization, reactivity and antifungal activity
Chaudhry,Bandna, Kumari,Bhatt,Sharma, Neeraj,Sagar, Anand
experimental part, p. 391 - 400 (2009/10/09)
Bivalent tin(II)-4-methoxyphenoxide of composition Sn(OC6H 4OMe-4)2 (1) has been synthesized from the reaction of SnCl2 with bimolar amounts of 4-methoxyphenol and diethylamine in tetrahydrofuran and characteriz
Free Radical Combination Reactions Involving Phenoxyl Radicals
Jonsson, M.,Lind, J.,Reitberger, T.,Eriksen, T. E.,Merenyi, G.
, p. 8229 - 8233 (2007/10/02)
The rates of phenoxyl radical reactions with the superoxide anion radical, O2.-, a peroxyl radical, HOC(CH3)2CH2OO., and an alkyl radical, HOC(CH3)2CH2., in aqueous solution have been measured for 15 different phenoxyl radicals by means of pulse radiolysis.In addition, the one-electron reduction potentials of 10 phenoxyl radicals have been determined.The fraction of electron transfer in the reaction of phenoxyl radicals with O2.- was determined by analysis of γ-irradiated samples.The experimental data can be accommodated by the Marcus theory for electron transfer, with the reorganization energy λ0 = 155 kJ/mol for the reaction between O2.- and phenoxyl radicals.
