Dimethylallyltryptophan synthase. An enzyme-catalyzed electrophilic aromatic substitution
摘要:
Dimethylallyltryptophan (DMAT) synthase catalyzes the alkylation of L-tryptophan at C(4) by dimethylallyl diphosphate (DMAPP) in the first pathway-specific step in the biosynthesis of ergot alkaloids. The mechanism of the reaction was studied with analogs of both substrates. Five 7-substituted derivatives of N-acetyltryptophan (2, Z = OCH3, CH3, F, CF3, and NO2) were synthesized. The L enantiomers of the free amino acids were obtained by selective hydrolysis of the racemate using aminoacylase from Aspergillus. In addition, the E and Z fluoromethyl and difluoromethyl analogs of DMAPP (1, Y = CH3, CH2F, CHF2) were prepared. Rates of the enzyme-catalyzed reactions were measured for the dimethylallyl derivatives with L-tryptophan and for the L-tryptophan derivatives with DMAPP. In addition, the relative reactivities of the methanesulfonate derivatives of the DMAPP analogs were determined for solvolysis in aqueous acetone. A Hammett plot for the tryptophan analogs gave a good linear correlation with rho = -2.0. In addition, a Hammett plot of the logarithms of the relative rates of solvolysis and enzyme-catalyzed alkylation gave a positive linear correlation. These results indicate that the prenyl-transfer reaction catalyzed by DMAT synthase is an electrophilic aromatic substitution and is mechanistically similar to the electrophilic alkylation catalyzed by farnesyl diphosphate synthase.
[EN] RAS BINDING PEPTIDES AND METHODS OF USE<br/>[FR] PEPTIDES DE LIAISON À RAS ET MÉTHODES D'UTILISATION
申请人:RA PHARMACEUTICALS INC
公开号:WO2017181061A1
公开(公告)日:2017-10-19
The present invention provides Ras modulators including inhibitors and/or antagonists of Ras, Ras binding, and Ras-dependent cell signaling activity. Also provided are methods of utilizing the Ras modulators as therapeutics.
The present invention relates to compounds and pharmaceutical preparations and their use in therapy for preventing or treating trauma, ischemia, stroke and degenerative diseases associated with cell death. Methods and compositions of the invention are particularly useful for treating neurological disorders associated with cellular necrosis.
[EN] HIGHLY ACTIVE SELF-SUFFICIENT NITRATION BIOCATALYSTS<br/>[FR] BIOCATALYSEURS DE NITRATION AUTO-SUFFISANTS HAUTEMENT ACTIFS
申请人:UNIV FLORIDA
公开号:WO2018081456A1
公开(公告)日:2018-05-03
The disclosure relates to the field of fusion proteins. In some aspects, the disclosure relates to artificial fusion proteins comprising cytochrome P450 enzymes linked to reductase enzymes and uses thereof. In some aspects, the disclosure relates to compounds produced by artificial cytochrome P450 enzymes.
The present invention relates to compounds and pharmaceutical preparations and their use in therapy for preventing or treating trauma, ischemia, stroke and degenerative diseases associated with cell death. Methods and compositions of the invention are particularly useful for treating neurological disorders associated with cellular necrosis.
L-tryptophan producing microorganisms are constructed by incorporating, into a recipient strain of the genus Bacillus, a recombinant plasmid containing a DNA fragment controlling resistance to a tryptophan-antagonist, which DNA fragment is obtained from chromosal DNA of a mutantof the genus Bacillus resistant to the tryptophan-antagonist.
将含有控制对色氨酸拮抗剂抗性的 DNA 片段的重组质粒加入芽孢杆菌属的受体菌株中,就能构建生产 L-色氨酸的微生物,该 DNA 片段是从对色氨酸拮抗剂具有抗性的芽孢杆菌属突变体的染色质 DNA 中获得的。