CH···O Interactions Are Not the Cause of Trends in Reactivity and Secondary Kinetic Isotope Effects for Enzymatic SN2 Methyl Transfer Reactions
نویسندگان
چکیده
Compaction matters: SN2 substitution represents an important class of reaction for both chemical and biological systems. The ability to assess enzymatic transition state structure within this class of reaction remains a major experimental challenge. Here, we comment on and compare the relative impact of compaction along the axis of reaction to the impact of an orthogonal CH···O hydrogen bonding interaction. The latter is concluded to play a limited role in determining relative reaction rates and secondary KIEs derived from experimental structureactivity correlations.
منابع مشابه
Influence of Equatorial CH⋅⋅⋅O Interactions on Secondary Kinetic Isotope Effects for Methyl Transfer
DFT calculations for methyl cation complexed within a constrained cage of water molecules permit the controlled manipulation of the "axial" donor/acceptor distance and the "equatorial" distance to hydrogen-bond acceptors. The kinetic isotope effect k(CH3)/k(CT3) for methyl transfer within a cage with a short axial distance becomes less inverse for shorter equatorial C⋅⋅⋅O distances: a decrease ...
متن کاملReactions of α-Nucleophiles with Alkyl Chlorides: Competition between SN2 and E2 Mechanisms and the Gas-Phase α-Effect
Reaction rate constants and deuterium kinetic isotope effects for the reactions of BrOwith RCl (R ) methyl, ethyl, isopropyl, and tert-butyl) were measured using a tandem flowing afterglow-selected ion flow tube instrument. These results provide qualitative insight into the competition between two classical organic mechanisms, nucleophilic substitution (SN2) and base-induced elimination (E2). A...
متن کاملReactivity of chemisorbed oxygen atoms and their catalytic consequences during CH4-O2 catalysis on supported Pt clusters.
Kinetic and isotopic data and density functional theory treatments provide evidence for the elementary steps and the active site requirements involved in the four distinct kinetic regimes observed during CH(4) oxidation reactions using O(2), H(2)O, or CO(2) as oxidants on Pt clusters. These four regimes exhibit distinct rate equations because of the involvement of different kinetically relevant...
متن کاملIsotopic and Kinetic Assessment of the Mechanism of CH
Additional resources and features associated with this article are available within the HTML version: • Supporting Information • Access to high resolution figures • Links to articles and content related to this article • Copyright permission to reproduce figures and/or text from this article This study provides kinetic and isotopic evidence for the identity and kinetic relevance of elementary s...
متن کاملConvergent Mechanistic Features between the Structurally Diverse N- and O-Methyltransferases: Glycine N-Methyltransferase and Catechol O-Methyltransferase
Although an enormous and still growing number of biologically diverse methyltransferases have been reported and identified, a comprehensive understanding of the enzymatic methyl transfer mechanism is still lacking. Glycine N-methyltransferase (GNMT), a member of the family that acts on small metabolites as the substrate, catalyzes methyl transfer from S-adenosyl-l-methionine (AdoMet) to glycine...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2016