1643-28-3Relevant articles and documents
Characterization of a carbon-carbon hydrolase from Mycobacterium tuberculosis involved in cholesterol metabolism
Lack, Nathan A.,Yam, Katherine C.,Lowe, Edward E.,Horsman, Geoff P.,Owen, Robin L.,Sim, Edith,Eltis, Lindsay D.
, p. 434 - 443 (2010)
In the recently identified cholesterol catabolic pathway of Mycobacterium tuberculosis, 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate hydrolase (HsaD) is proposed to catalyze the hydrolysis of a carbon-carbon bond in 4,5-9,10-diseco-3-hydroxy-5,9,17-tri-oxoandrosta-1 (10),2-diene-4-oic acid (DSHA), the cholesterol meta-cleavage product (MCP) and has been implicated in the intracellular survival of the pathogen. Herein, purified HsaD demonstrated 4-33 times higher specificity for DSHA (kcat/Km = 3.3 ± 0.3 × 104 M-1 s-1) than for the biphenyl MCP 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) and the synthetic analogue 8-(2-chlorophenyl)-2-hydroxy-5-methyl-6-oxoocta-2, 4-dienoic acid (HOPODA), respectively. The S114A variant of HsaD, in which the active site serine was substituted with alanine, was catalytically impaired and bound DSHA with a Kd of 51 ± 2 μM. The S114A·DSHA species absorbed maximally at 456 nm, 60 nm red-shifted versus the DSHA enolate. Crystal structures of the variant in complex with HOPDA, HOPODA, or DSHA to 1.8 -1.9 A indicate that this shift is due to the enzyme-induced strain of the enolate. These data indicate that the catalytic serine catalyzes tautomerization. A second role for this residue is suggested by a solvent molecule whose position in all structures is consistent with its activation by the serine for the nucleophilic attack of the substrate. Finally, the α-helical lid covering the active site displayed a ligand-dependent conformational change involving differences in side chain carbon positions of up to 6.7 A, supporting a two-conformation enzymatic mechanism. Overall, these results provide novel insights into the determinants of specificity in a mycobacterial cholesterol-degrading enzyme as well as into the mechanism of MCP hydrolases.
Method for synthesizing phenylpropionic acid compounds through heterogeneous palladium metal catalysis
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Paragraph 0070-0076, (2021/04/21)
The invention discloses a method for synthesizing phenylpropionic acid compounds by heterogeneous catalysis. The method comprises the following steps: sequentially adding Pd@POL, toluene, styrene, formic acid and acetic anhydride into a reaction flask, stirring the reaction mixture at 80 DEG C to react, cooling the reaction solution to room temperature after the reaction is finished, diluting with dichloromethane, and transferring the solution into a separating funnel, washing with a sodium hydroxide solution, acidifying the water layer with a hydrochloric acid aqueous solution, extracting with dichloromethane, merging organic phases, drying with anhydrous sodium sulfate, and carrying out vacuum concentration to obtain the phenylpropionic acid compound. The method can remove heavy metal residues, is green and environment-friendly, is simple to operate and easy to implement, and the prepared phenylpropionic acid compound has a good application prospect.
Cyclohexyl-Fused, Spirobiindane-Derived, Phosphine-Catalyzed Synthesis of Tricyclic ?3-Lactams and Kinetic Resolution of ?3-Substituted Allenoates
Wu, Mingyue,Han, Zhaobin,Li, Kaizhi,Wu, Ji'En,Ding, Kuiling,Lu, Yixin
supporting information, p. 16362 - 16373 (2019/10/16)
A C2-symmetric chiral phosphine catalyst, NUSIOC-Phos, which can be easily derived from cyclohexyl-fused spirobiindane, was introduced. A highly enantioselective domino process involving pyrrolidine-2,3-diones and γ-substituted allenoates catalyzed by NUSIOC-Phos has been disclosed. Diastereospecific tricyclic γ-lactams containing five contiguous stereogenic centers were obtained in high yields and with nearly perfect enantioselectivities. A kinetic resolution process of racemic γ-substituted allenoates was developed for the generation of optically enriched chiral allenoates.
