3158-42-7Relevant articles and documents
Unexpected Reactions of α,β-Unsaturated Fatty Acids Provide Insight into the Mechanisms of CYP152 Peroxygenases
Jiang, Yuanyuan,Li, Shengying,Li, Zhong,Peng, Wei,Tang, Dandan,Wang, Binju,You, Cai,Zhao, Yue
supporting information, p. 24694 - 24701 (2021/10/14)
CYP152 peroxygenases catalyze decarboxylation and hydroxylation of fatty acids using H2O2 as cofactor. To understand the molecular basis for the chemo- and regioselectivity of these unique P450 enzymes, we analyze the activities of three CYP152 peroxygenases (OleTJE, P450SPα, P450BSβ) towards cis- and trans-dodecenoic acids as substrate probes. The unexpected 6S-hydroxylation of the trans-isomer and 4R-hydroxylation of the cis-isomer by OleTJE, and molecular docking results suggest that the unprecedented selectivity is due to OleTJE’s preference of C2?C3 cis-configuration. In addition to the common epoxide products, undecanal is the unexpected major product of P450SPα and P450BSβ regardless of the cis/trans-configuration of substrates. The combined H218O2 tracing experiments, MD simulations, and QM/MM calculations unravel an unusual mechanism for Compound I-mediated aldehyde formation in which the active site water derived from H2O2 activation is involved in the generation of a four-membered ring lactone intermediate. These findings provide new insights into the unusual mechanisms of CYP152 peroxygenases.
Oxidation of some α-hydroxy acids by tetraethylammonium chlorochromate: A kinetic and mechanistic study
Swami, Preeti,Yajurvedi,Mishra,Sharma, Pradeep K.
experimental part, p. 50 - 55 (2010/04/06)
The oxidation of glycolic, lactic, malic, and a few substituted mandelic acids by tetraethylammonium chlorochromate (TEACC) in dimethylsulfoxide leads to the formation of corresponding oxoacids. The reaction is first order each in TEACC and hydroxy acids. Reaction is failed to induce the polymerization of acrylonitrile. The oxidation of α-deuteriomandelic acid shows the presence of a primary kinetic isotope effect (kH/kD = 5.63 at 298 K). The reaction does not exhibit the solvent isotope effect. The reaction is catalyzed by the hydrogen ions. The hydrogen ion dependence has the following form: kobs = a + b[H+ ]. Oxidation of p-methylmandelic acid has been studied in 19 different organic solvents. The solvent effect has been analyzed by using Kamlet's and Swain's multiparametric equations. A mechanism involving a hydride ion transfer via a chromate ester is proposed.
Afroside, a 15β-Hydroxycardenolide
Cheung, H.T. Andrew,Coombe, Reginald G.,Sidwell, William T. L.,Watson, Thomas R.
, p. 64 - 72 (2007/10/02)
Afroside (2) has the same carbohydrate as gomphoside (1), namely a 4,6-dideoxyhexosulose doubly linked to the aglycone at the 2α and 3β positions.It differs from gomphoside in having a 15β-hydroxy-group, the location of which is shown by n.m.r. (1H and 13C) and mass spectra, and is established by the formation of a 14,15-cyclic carbonate derivative (2e).The 14β,15β-diol group shows unusual inertness to glycol cleavage and to OO-isopropylidene derivative formation, in contrast with the behaviour of the 2',3'-diol in the carbohydrate, and the 2α,3β-diol in the genin, afrogenin (4).Degradation of the carbohydrate in afroside gave afrogenin (4), and 'anhydroafrogenin' (9) which is a 15-ketone with 14α-H.The conformation of the highly crowded ring D is studied using 1H and 13C n.m.r.
