Enantioselective resolution of (R,S)-DMPM to prepare (R)-DMPM by an adsorbed-covalent crosslinked esterase PAE07 from Pseudochrobactrum asaccharolyticum WZZ003.

(R)-N-(2,6-dimethylphenyl) aminopropionic acid methyl ester ((R)-DMPM) is an important chiral intermediate of the fungicide N-(2,6-Dimethylphenyl)-N-(methoxyacetyl)-alanine methyl ester ((R)-Metalaxyl). In this study, (1) D3520 (macroporous acrylic anion resin), selected from the ten resins, was used to immobilize the esterase from Pseudochrobactrum asaccharolyticum WZZ003 (PAE07) for resoluting the (R,S)-DMPM to obtain (R)-DMPM. (2) Up to 20 g/L PAE07 could be immobilized onto D3520 with a high enzymatic activity of 32.

Purification, identification and characterization of an esterase with high enantioselectivity to (S)-ethyl indoline-2-carboxylate.

Objective: To purify an esterase which can selectively hydrolyze (R,S)-ethyl indoline-2-carboxylate to produce (S)-indoline-2-carboxylic acid and characterize its enzymatic properties.

Results: An intracellular esterase from Bacillus aryabhattai B8W22 was isolated and the purified protein was identified as a carboxylesterase by MALDI-TOF mass spectrometry. The enzyme (named BaCE) was 59.

High-level expression and characterization of a stereoselective lipase from Aspergillus oryzae in Pichia pastoris.

Pichia pastoris expression is a mature and efficient eukaryotic expression system. In this work, Aspergillus oryzae lipase (AOL, with the molecular mass of 28 kDa), which can perform highly stereoselective hydrolysis of (R, S)-methyl 2-(4-hydroxyphenoxy) propanoate, was expressed in P. pastoris X-33.

Rapid synthesis of flavone-based monoamine oxidase (MAO) inhibitors targeting two active sites using click chemistry.

A new library of flavone derivatives targeting two active sites of monoamine oxidases ("aromatic cage" and substrate cavity) were designed and synthesized using click chemistry (CuAAC reaction) between 6-N -2-phenyl chromones (Az1-Az2) and a series of alkynes (k1-k20). Their inhibitory activities against MAO isoforms (MAO-A and MAO-B) are evaluated. Compounds with fluorine, amide bonds, or amino bonds have shown better inhibition.

Influence of ammonium salts on the lipase/esterase activity assay using p-nitrophenyl esters as substrates.

p-Nitrophenyl esters with a short-chain carboxylic group, such as p-nitrophenyl acetate (p-NPA) and p-nitrophenyl butyrate (p-NPB), could be effectively hydrolyzed by ammonium salts. p-Nitrophenyl esters were usually used as substrates to assay the lipase/esterase activity. Ammonium sulfate precipitation was often used to purify proteins, and some ammonium salts were usually used as nitrogen sources or inorganic salts for the lipase/esterase production.

N-(2-Iodo-phen-yl)benzene-carbox-imid-amide.

The title compound, C(13)H(11)IN(2), crystallizes with two independent molecules (A and B) in the asymmetric unit. The two aromatic rings are inclined to one another by 73.3 (2)° in molecule A, and by 74.

4,5,6,7-Tetra-chloro-N-(2,3,4-trifluoro-phen-yl)phthalimide.

The asymmetric unit of the title compound, C(14)H(2)Cl(4)F(3)NO(2), contains two independent mol-ecules. In each mol-ecule, the phthalimide ring system is nearly planar [maximum atomic deviation = 0.031 (2) or 0.