苯甲酰氯 、 TAN 950A 在
碳酸氢钠 作用下,
以
水 为溶剂,
反应 4.0h,
以68%的产率得到N-benzoyl TAN-950 A
参考文献:
名称:
A novel amino acid antibiotic tan-950
摘要:
A novel antifungal antibiotic, TAN-950 A, was isolated from the culture filtrate of Streptomyces platensis A-136. Its structure was determined to be (S)-2-amino-3-(isoxazolin-5-on-4-yl)-propanoic acid. Minor components, TAN-950 B, C, D and E, were found to be present in an equilibrium mixture containing TAN-950 A. Their structures were determined from spectral analyses, X-ray crystallographic analysis and synthesis from L-glutamic acid.
A novel antifungal antibiotic, TAN-950 A, was isolated from the culture filtrate of Streptomyces platensis A-136. Its structure was determined to be (S)-2-amino-3-(isoxazolin-5-on-4-yl)-propanoic acid. Minor components, TAN-950 B, C, D and E, were found to be present in an equilibrium mixture containing TAN-950 A. Their structures were determined from spectral analyses, X-ray crystallographic analysis and synthesis from L-glutamic acid.
isoxazolylalanine isomers, beta-(isoxazolin-5-on-2-yl)-L-alanine (BIA, 1) and beta-(isoxazolin-5-on-4-yl)-L- alanine (TAN-950A, 2) were confirmed to be derived from O-acetyl-L-serine (OAS) and isoxazolin-5-one by cysteine synthases (CSases) with a different ratio in different plant parts. Some properties of this enzyme in the biosynthesis of both isomers are described.
PARA-NITROBENZYL ESTERASES WITH ENHANCED ACTIVITY IN AQUEOUS AND NONAQUEOUS MEDIA
申请人:CALIFORNIA INSTITUTE OF TECHNOLOGY
公开号:EP0876490A1
公开(公告)日:1998-11-11
US5741691A
申请人:——
公开号:US5741691A
公开(公告)日:1998-04-21
US5945325A
申请人:——
公开号:US5945325A
公开(公告)日:1999-08-31
[EN] PARA-NITROBENZYL ESTERASES WITH ENHANCED ACTIVITY IN AQUEOUS AND NONAQUEOUS MEDIA<br/>[FR] PARA-NITROBENZYLE ESTERASES A ACTIVITE RENFORCEE EN MILIEUX AQUEUX ET NON AQUEUX
申请人:——
公开号:WO1997027304A1
公开(公告)日:1997-07-31
[EN] A method for isolating and identifying modified para-nitrobenzyl esterases which exhibit improved stability and/or esterase hydrolysis activity toward selected substrates and under selected reaction conditions relative to the unmodified para-nitrobenzyl esterase. The method involves preparing a library of modified para-nitrobenzyl esterase nucleic acid segments (genes) which have nucleotide sequences that differ from the nucleic acid segment which encodes for unmodified para-nitrobenzyl esterase. The library of modified para-nitrobenzyl nucleic acid segments is expressed to provide a plurality of modified enzymes. The clones expressing modified enzymes are then screened to identify which enyzmes have improved esterase activity by measuring the ability of the enzymes to hydrolyze the selected substrate under the selected reaction conditions. Specific modified para-nitrobenzyl esterases are disclosed which have improved stability and/or ester hydrolysis activity in aqueous or aqueous-organic media relative to the stability and/or ester hydrolysis activity of unmodified naturally occurring para-nitrobenzyl esterase. [FR] Procédé permettant d'isoler et d'identifier des para-nitrobenzyle estérases modifiées présentant une stabilité améliorée et/ou une activité d'hydrolyse d'estérase envers des substrats choisis et dans des conditions de réaction choisies par rapport à la para-nitrobenzyle estérase non modifiée. Le procédé consiste à préparer une bibliothèque de segments d'acides nucléiques (gènes) de para-nitrobenzyle estérase présentant des séquences de nucléotides qui diffèrent du segment d'acide nucléique codant la para-nitrobenzyle estérase non modifiée. La bibliothèque de segments d'acide nucléique de para-nitrobenzyle est exprimée de façon à donner une pluralité d'enzymes modifiées. Les clones exprimant les enzymes modifiés sont ensuite criblés, ce qui permet d'identifier les enzymes qui ont amélioré l'activité de l'estérase en mesurant la capacité des enzymes à hydrolyser le substrat choisi dans les conditions de réaction choisies. Sont décrites également des para-nitrobenzyle estérases modifiées spécifiques présentant une stabilité et/ou une activité d'hydrolyse d'ester accrues dans des milieux aqueux ou aqueux organiques, par rapport à la stabilité et/ou à l'activité d'hydrolyse d'ester des para-nitrobenzyle estérases d'origine naturelle non modifiées.