1460-34-0Relevant articles and documents
Construction of an L-isoleucine overproducing strain of Escherichia coli K-12
Hashiguchi, Ken-Ichi,Takesada, Hiroko,Suzuki, Eiichiro,Matsui, Hiroshi
, p. 672 - 679 (1999)
The genes for a threonine deaminase that is resistant to feedback inhibition by L-isoleucine and for an active acetohydroxyacid synthase II were introduced by a plasmid into a L-threonine-producing recombinant strain of Escherichia coli K-12. Analysis of culture broth of the strain using 13C nuclear magnetic resonance suggested that α, β-dihydroxy-β-methylvalerate (DHMV) and α-keto-βmethylvalerate (KMV), the third and the fourth intermediates in the L-isoleucine biosynthetic pathway from L-threonine, respectively, accumulated in the medium in amounts comparable to that of L-isoleucine. The ratio of accumulated L-isoleucine:DHMV:KMV were approximately 2:1:1. The concentration of accumulated L-isoleucine increased by twofold after the additional introduction of the genes for dihyroxyacid dehydratase (DH) and transaminase-B (TA-B), and the intermediates no longer accumulated. The resultant strain TVD5 accumulated 10 g/1 of L-isoleucine from 40 g/1 of glucose.
Production of α-Ketoisocaproate and α-Keto-β-Methylvalerate by Engineered L-Amino Acid Deaminase
Yuan, Yuxiang,Song, Wei,Liu, Jia,Chen, Xiulai,Luo, Qiuling,Liu, Liming
, p. 2464 - 2472 (2019)
This study aimed to develop an efficient enzymatic strategy for industrial production of α-ketoisocaproate (α-KIC) and α-keto-β-methylvalerate (α-KMV) from L-leucine and L-isoleucine, respectively. L-amino acid deaminase from Proteus mirabilis (PmLAAD) was heterologously expressed in E. coli BL21(DE3) and modified to increase its catalytic efficiency by engineering the PmLAAD substrate-binding cavity and entrance tunnel. Four essential residues (Q92, M440, T436, and W438) were identified from structural analysis and molecular dynamics simulations. Residue Q92 was mutated to alanine, and the volume of the binding cavity, enzyme activity, and the kcat/Km value of mutant PmLAAD Q92A increased to 994.2 ?3, 191.36 U mg?1, and 1.23 mM?1 min?1, respectively; consequently, the titer and conversion rate of α-KIC from L-leucine were 107.1 g L?1 and 98.1 %, respectively. For mutant PmLAADT436/W438A, the entrance tunnel, enzyme activity, and the kcat/Km value increased to 1.71 ?, 170.12 U mg?1, and 0.70 mM?1 min?1, respectively; consequently, the titer and conversion rate of α-KMV from L-isoleucine were 98.9 g L?1 and 99.7 %, respectively. Therefore, augmentation of the substrate-binding cavity and entrance tunnel of PmLAAD can facilitate efficient industrial synthesis of α-KIC and α-KMV.
Heterocyclic Compounds from the Mushroom Albatrellus confluens and Their Inhibitions against Lipopolysaccharides-Induced B Lymphocyte Cell Proliferation
Zhang, Shuaibing,Huang, Ying,He, Shijun,Chen, Heping,Wu, Bin,Li, Shanyong,Zhao, Zhenzhu,Li, Zhenghui,Wang, Xian,Zuo, Jianping,Feng, Tao,Liu, Jikai
, p. 10158 - 10165 (2018)
Eight hetereocyclic compounds conflamides B-I with an unprecedented skeleton and their precursor conflamide A were isolated from the mushroom Albatrellus confluens. Their structures and absolute configurations were determined by use of NMR studies, total synthesis, and calculated ECD spectra. Conflamides D and E were found to exhibit potent inhibition against LPS-induced B lymphocyte cell proliferation with IC50 values 1.48 and 5.71 μM, respectively.
Asymmetric C-Alkylation by the S-Adenosylmethionine-Dependent Methyltransferase SgvM
Sommer-Kamann, Christina,Fries, Alexander,Mordhorst, Silja,Andexer, Jennifer N.,Müller, Michael
, p. 4033 - 4036 (2017)
S-Adenosylmethionine-dependent methyltransferases (MTs) play a decisive role in the biosynthesis of natural products and in epigenetic processes. MTs catalyze the methylation of heteroatoms and even of carbon atoms, which, in many cases, is a challenging reaction in conventional synthesis. However, C-MTs are often highly substrate-specific. Herein, we show that SgvM from Streptomyces griseoviridis features an extended substrate scope with respect to the nucleophile as well as the electrophile. Aside from its physiological substrate 4-methyl-2-oxovalerate, SgvM catalyzes the (di)methylation of pyruvate, 2-oxobutyrate, 2-oxovalerate, and phenylpyruvate at the β-carbon atom. Chiral-phase HPLC analysis revealed that the methylation of 2-oxovalerate occurs with R selectivity while the ethylation of 2-oxobutyrate with S-adenosylethionine results in the S enantiomer of 3-methyl-2-oxovalerate. Thus SgvM could be a valuable tool for asymmetric biocatalytic C-alkylation reactions.
Chemoenzymatic Production of Enantiocomplementary 2-Substituted 3-Hydroxycarboxylic Acids from l-α-Amino Acids
Pickl, Mathias,Marín-Valls, Roser,Joglar, Jesús,Bujons, Jordi,Clapés, Pere
, p. 2866 - 2876 (2021/04/14)
A two-enzyme cascade reaction plus in situ oxidative decarboxylation for the transformation of readily available canonical and non-canonical l-α-amino acids into 2-substituted 3-hydroxycarboxylic acid derivatives is described. The biocatalytic cascade consisted of an oxidative deamination of l-α-amino acids by an l-α-amino acid deaminase from Cosenzaea myxofaciens, rendering 2-oxoacid intermediates, with an ensuing aldol addition reaction to formaldehyde, catalyzed by metal-dependent (R)- or (S)-selective carboligases namely 2-oxo-3-deoxy-l-rhamnonate aldolase (YfaU) and ketopantoate hydroxymethyltransferase (KPHMT), respectively, furnishing 3-substituted 4-hydroxy-2-oxoacids. The overall substrate conversion was optimized by balancing biocatalyst loading and amino acid and formaldehyde concentrations, yielding 36–98% aldol adduct formation and 91–98% ee for each enantiomer. Subsequent in situ follow-up chemistry via hydrogen peroxide-driven oxidative decarboxylation afforded the corresponding 2-substituted 3-hydroxycarboxylic acid derivatives. (Figure presented.).
Biocatalytic Construction of Quaternary Centers by Aldol Addition of 3,3-Disubstituted 2-Oxoacid Derivatives to Aldehydes
Marín-Valls, Roser,Hernández, Karel,Bolte, Michael,Parella, Teodor,Joglar, Jesús,Bujons, Jordi,Clapés, Pere
supporting information, p. 19754 - 19762 (2020/12/01)
The congested nature of quaternary carbons hinders their preparation, most notably when stereocontrol is required. Here we report a biocatalytic method for the creation of quaternary carbon centers with broad substrate scope, leading to different compound classes bearing this structural feature. The key step comprises the aldol addition of 3,3-disubstituted 2-oxoacids to aldehydes catalyzed by metal dependent 3-methyl-2-oxobutanoate hydroxymethyltransferase from E. coli (KPHMT) and variants thereof. The 3,3,3-trisubstituted 2-oxoacids thus produced were converted into 2-oxolactones and 3-hydroxy acids and directly to ulosonic acid derivatives, all bearing gem-dialkyl, gem-cycloalkyl, and spirocyclic quaternary centers. In addition, some of these reactions use a single enantiomer from racemic nucleophiles to afford stereopure quaternary carbons. The notable substrate tolerance and stereocontrol of these enzymes are indicative of their potential for the synthesis of structurally intricate molecules.
The pseudoalteromonas luteoviolacea L-amino acid oxidase with antimicrobial activity is a flavoenzyme
Andreo-Vidal, Andrés,Sanchez-Amat, Antonio,Campillo-Brocal, Jonatan C.
, (2019/01/03)
The marine environment is a rich source of antimicrobial compounds with promising pharmaceutical and biotechnological applications. The Pseudoalteromonas genus harbors one of the highest proportions of bacterial species producing antimicrobial molecules. For decades, the presence of proteins with L-amino acid oxidase (LAAO) and antimicrobial activity in Pseudoalteromonas luteoviolacea has been known. Here, we present for the first time the identification, cloning, characterization and phylogenetic analysis of Pl-LAAO, the enzyme responsible for both LAAO and antimicrobial activity in P. luteoviolacea strain CPMOR-2. Pl-LAAO is a flavoprotein of a broad substrate range, in which the hydrogen peroxide generated in the LAAO reaction is responsible for the antimicrobial activity. So far, no protein with a sequence similarity to Pl-LAAO has been cloned or characterized, with this being the first report on a flavin adenine dinucleotide (FAD)-containing LAAO with antimicrobial activity from a marine microorganism. Our results revealed that 20.4% of the sequenced Pseudoalteromonas strains (specifically, 66.6% of P. luteoviolacea strains) contain Pl-laao similar genes, which constitutes a well-defined phylogenetic group. In summary, this work provides insights into the biological significance of antimicrobial LAAOs in the Pseudoalteromonas genus and shows an effective approach for the detection of novel LAAOs, whose study may be useful for biotechnological applications.
A method for preparing calcium isoleucine racemization alkone
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Paragraph 0029; 0030; 0031, (2016/12/22)
The invention discloses a method for preparing calcium 3-methyl-2-oxovalerate. The method comprises the following steps of: dripping diethyl oxalate into an alcoholic solution of sodium alkoxide; dripping 2-methyl butyraldehyde, keeping the temperature, stirring, adding an alkali solution, regulating the acid after heat insulation is ended, extracting, and adding a certain amount of water into an extracting solution; adding the alkali solution to regulate the pH, dripping an aqueous solution of calcium chloride for salifying to obtain the coarse 3-methyl-2-oxovalerate product; and refining the coarse 3-methyl-2-oxovalerate product in a mixed solvent of purified water and organic solvent, and obtaining the refined 3-methyl-2-oxovalerate product. The process is mild in reaction conditions, easy to operate, fewer in steps, high in yield and high in quality, the adopted raw materials are cheap and basically do not cause pollution, waste gas and lots of waste residues are avoided, and the method is suitable for industrial production.
NOVEL COMPOUND, PHARMACEUTICALLY ACCEPTABLE SALT OR OPTICAL ISOMER THEREOF, METHOD FOR PREPARING SAME, AND PHARMACEUTICAL COMPOSITION FOR PREVENTION OR TREATMENT OF VIRAL DISEASES CONTAINING SAME AS ACTIVE INGREDIENT
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Paragraph 0105; 107, (2015/11/16)
The present invention relates to a novel compound, to a pharmaceutically acceptable salt or optical isomer thereof, to a method for preparing same, and to a pharmaceutical composition for the prevention or treatment of viral diseases containing same as an active ingredient. The novel compound according to the present invention not only has low cytotoxicity but also has excellent antiviral activity against picornavirus such as coxsackievirus, enterovirus, echovirus, poliovirus and rhinovirus, and thus can be effectively used as a pharmaceutical composition for the prevention or treatment of viral diseases such as infantile paralysis, acute hemorrhagic conjunctivitis, viral meningitis, hand-foot-and-mouth disease, vesicular disease, hepatitis A, myitis, myocarditis, pancreatitis, diabetes, epidemic myalgia, encephalitis, cold, herpangina, foot-and-mouth disease, asthma, chronic obstructive pulmonary disease, pneumonia, sinus infection, or otitis media.
Stereoselective synthesis of l-tert-leucine by a newly cloned leucine dehydrogenase from Exiguobacterium sibiricum
Li, Jing,Pan, Jiang,Zhang, Jie,Xu, Jian-He
, p. 11 - 17 (2014/05/06)
A leucine dehydrogenase from Exiguobacterium sibiricum (EsLeuDH) was discovered by genome mining approach. The EsLeuDH was overexpressed in Escherichia coli BL21, purified to homogeneity and characterized. This enzyme showed good thermostability with a half-life of 3.1 h at 60 °C. Furthermore, EsLeuDH has a broad spectrum of substrate specificity, showing activities toward many aliphatic α-keto acids and L-amino acids, in addition to some aryl α-keto acids and aryl α-amino acids, such as α-oxobenzeneacetic and l-phenylglycine. The EsLeuDH was successfully coexpressed with Bacillus megaterium glucose dehydrogenase (BmGDH) in Escherichia coli BL21 for the production of l-tert-leucine. By using the coexpressed whole cells, a decagram preparation of l-tert-leucine was performed at a substrate concentration of 0.6 M (78.1 g L-1) in 1 L scale with 99% conversion after 5.5 h, resulting in 80.1% yield and > 99% ee (enantiomeric excess).2014 Published by Elsevier B.V.
