Towards a novel explanation of Pseudomonas cepacia lipase enantioselectivity via molecular modelling of the enantiomer trajectory into the active site was written by Guieysse, David;Salagnad, Christophe;Monsan, Pierre;Remaud-Simeon, Magali;Tran, Vinh. And the article was included in Tetrahedron: Asymmetry in 2003.Quality Control of Ethyl (2-bromophenyl)acetate This article mentions the following:
In the transesterification reaction between (RS)-2-bromophenyl acetic acid Et ester and 1-octanol in n-octane, Pseudomonas cepacia lipase enantioselectivity towards the (R)-isomer is 57. Two strategies are described to investigate the structural basis involved in this enzyme enantioselectivity. Mol. modeling of the tetrahedral intermediate mimicking the transition state enables the identification of two potentially productive substrate-binding modes for each enantiomer. However, the conformations obtained with the faster and slower-reacting enantiomers have equivalent potential energies and most of them possess the hydrogen bonds essential for catalysis. On this basis, it is not possible to distinguish the diastereomeric complexes. The second approach is original and consists in a simple but robust protocol of pseudomol. dynamics simulations under constraints to map the probable trajectory of the enantiomers in the active site. Enzyme/substrate interaction energy is always found to be lower for the faster-reacting enantiomer, which satisfactorily corroborates the exptl. results. Energy differences are attributed to specific interactions of these substrates with a network of hydrophobic residues lining the access path. Furthermore, mechanistic details suggest that the pivoting side chains of the hydrophobic residues act in a concerted step-tooth gear motion whose basic role is to select and guide the substrates towards the active site. With this type of lipase, such dynamic features could be the key explanation of this as yet unexplored enantiorecognition. For the slower-reacting enantiomer, it appears that the concerted motion of the side chains is perturbed when the substrate passes through a bottleneck formed by Val266 and Leu17. The enantioselectivity of mutant Val266Leu with a more bulky side chain at this position supports our assumption: by narrowing the bottleneck, the enantioselectivity was considerably enhanced as much as up to 200. In the experiment, the researchers used many compounds, for example, Ethyl (2-bromophenyl)acetate (cas: 2178-24-7Quality Control of Ethyl (2-bromophenyl)acetate).
Ethyl (2-bromophenyl)acetate (cas: 2178-24-7) belongs to organobromine compounds. Bromo compounds are employed in a variety of metal-catalyzed coupling reactions. They are also ideal candidates for the synthesis of Grignard reagents that have wide-applicability in organic synthesis. alpha-Bromoesters are employed in the Reformatsky reaction for the synthesis of beta-hydroxyesters. One prominent application of synthetic organobromine compounds is the use of polybrominated diphenyl ethers as fire-retardants, and in fact fire-retardant manufacture is currently the major industrial use of the element bromine.Quality Control of Ethyl (2-bromophenyl)acetate
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary