90522-92-2Relevant academic research and scientific papers
Steric Course of the Allylic Rearrangement Catalyzed by β-Hydroxydecanoylthioester Dehydrase. Mechanistic Implications
Schwab, John M.,Klassen, John B.
, p. 7217 - 7227 (1984)
β-Hydroxydecanoylthioester dehydrase, which is the pivotal enzyme in the biosynthesis of unsaturated fatty acids in anaerobic metabolism, catalyses the equilibration of thio esters of (R)-3-hydroxydecanoic acid, (E)-2-decenoic acid, and (Z)-3-decenoic acid.On the basis of evidence available to date, both two-base and one-base mechanisms of action can be envisioned for dehydrase.In an effort to distinguish between these mechanisms, the stereochemical course of the dehydrase-catalyzed allylic rearrangement has been determined.N-Acetylcysteamine (NAC) thio esters of (R)- and (S)-(E)-decanoic acid were synthesized and incubated with dehydrase.The product (Z)-3-decenoyl-NAC was derivatized, and 2H NMR analysis showed that the pro-4R hydrogen had been removed. (E)-2-Decenoyl-NAC and unlabeled (E)-2-decenoyl NAC were incubated with dehydrase in 1H2O and 2H2O, respectively.Analysis of a derivative of the resulting labeled (Z)-3-decenoyl-NAC showed that protonation had occured on the si face at substrate C-2.The overall steric course of the reaction is therefore suprafacial.The significance of this result is discussed in terms of the mechanisms of the "normal" dehydrase-catalysed reactions as well as the "suicide" inactivation of the enzyme.
β-Hydroxydecanoylthioester Dehydrase. Steric Course at Substrate C-4 in the Enzyme-catalysed Allylic Rearrangement
Schwab, John M.,Klassen, John B.
, p. 296 - 297 (2007/10/02)
The pro-(4R) hydrogen is lost in the enzyme-catalysed rearrangement of the N-acetylcysteinamine thioester of E-dec-2-enoic acid to the corresponding thioester of Z-dec-3-enoic acid.
