38135-26-1Relevant articles and documents
A useful propionate cofactor enhancing activity for organic solvent-tolerant recombinant metal-free bromoperoxidase (perhydrolase) from Streptomyces aureofaciens
China, Hideyasu,Ogino, Hiroyasu
, p. 327 - 332 (2019/07/12)
The oxidative brominating activity of an organic solvent-tolerant recombinant metal-free bromoperoxidase BPO-A1 with C-terminal His-tag (rBPO-A1), from Streptomyces aureofaciens found to depend on various additives. These included carboxylic acids, used as cofactors and alcohols, used as water-miscible organic solvents. Enzyme activity was significantly enhanced by using propanoic acid (PA) as a cofactor, which had a high Log D at pH 5.0 and ethylene glycol with a low Log P. The positional specificity of oxidative hydroxybromination for olefins, using rBPO-A1 and PA in the presence of methanol, was higher compared to a non-enzymatic reaction using peracetic acid. The oxidative bromination step, occurring after enzymatic peroxidation step, is suggested to be pseudoenzymatic.
Efficient Intramolecular General Acid Catalysis of Enol Ether Hydrolysis. Hydrogen-bonding Stabilisation of the Transition State for Proton Transfer to Carbon
Kirby, Anthony J.,Williams, Nicholas H.
, p. 643 - 648 (2007/10/02)
The intrinsically low efficiency of intramolecular general acid-base catalysis is enhanced when the proton transfer generates a strong intramolecular hydrogen bond.This principle is shown to apply to proton transfer to carbon: the carboxy groups of methyl vinyl ethers 3E and 3Z derived from 2-carboxyphenylacetaldehyde act as general acids to catalyse the hydrolysis of the neighbouring enol ether groups with effective molarities (EM) of about 300 and 2000 M, respectively.The solvent deuterium isotope effects confirm that the usual mechanism for enol ether hydrolysis is operative.In this system the oxocarbocation intermediate is trapped by the neighbouring carboxylate group to give the acylal 6, rather than the formal product of hydrolysis.