328-42-7Relevant articles and documents
Structure Elucidation of Phomopsin A, a Novel Cyclic Hexapeptide Mycotoxin produced by Phomopsis leptostromiformis
Culvenor, Claude C. J.,Cockrum, Peter A.,Edgar, John A.,Frahn, John L.,Gorst-Allman, Charles P.,et al.
, p. 1259 - 1262 (1983)
Phomopsin A, the main mycotoxin isolated from cultures of Phomopsis leptostromiformis and the cause of lupinosis disease in animals grazing infected lupins, is a cyclic hexapeptide containing 3-hydroxyisoleucine, 3,4-didehydrovaline, N-methyl-3-(3-chloro-4,5-dihydroxyphenyl)-3-hydroxyalanine, E-2,3-didehydroaspartic acid, E-2,3-didehydroisoleucine, and 3,4-didehydroproline; its 13C n.m.r. spectrum was completely assigned and the amino-acid sequence established unambiguously by extensive heteronuclear 13C- selective population inversion n.m.r. experiments.
Purification, characterization, and overexpression of psychrophilic and thermolabile malate dehydrogenase of a novel antarctic psychrotolerant, Flavobacterium frigidimaris KUC-1
Oikawa, Tadao,Yamamoto, Noriko,Shimoke, Koji,Uesato, Shinichi,Ikeuchi, Toshihiko,Fujioka, Toru
, p. 2146 - 2154 (2005)
We purified the psychrophilic and thermolabile malate dehydrogenase to homogeneity from a novel psychrotolerant, Flavobacterium frigidimaris KUC-1, isolated from Antarctic seawater. The enzyme was a homotetramer with a molecular weight of about 123 k and that of the subunit was about 32 k. The enzyme required NAD(P)+ as a coenzyme and catalyzed the oxidation of L-malate and the reduction of oxalacetate specifically. The reaction proceeded through an ordered bi-bi mechanism. The enzyme was highly susceptible to heat treatment, and the half-life time at 40°C was estimated to be 3.0 min. The kcat/Km (μM-1·s-1) values for L-malate and NAD+ at 30°C were 289 and 2,790, respectively. The enzyme showed pro-R stereospecificity for hydrogen transfer at the C4 position of the nicotinamide moiety of the coenzyme. The enzyme contained 311 amino acid residues and much lower numbers of proline and arginine residues than other malate dehydrogenases.
Recombinant thermoactive phosphoenolpyruvate carboxylase (PEPC) from Thermosynechococcus elongatus and its coupling with mesophilic/thermophilic bacterial carbonic anhydrases (CAs) for the conversion of CO2 to oxaloacetate
Del Prete, Sonia,De Luca, Viviana,Capasso, Clemente,Supuran, Claudiu T.,Carginale, Vincenzo
, p. 220 - 225 (2016)
With the continuous increase of atmospheric CO2 in the last decades, efficient methods for carbon capture, sequestration, and utilization are urgently required. The possibility of converting CO2 into useful chemicals could be a good strategy to both decreasing the CO2 concentration and for achieving an efficient exploitation of this cheap carbon source. Recently, several single- and multi-enzyme systems for the catalytic conversion of CO2 mainly to bicarbonate have been implemented. In order to design and construct a catalytic system for the conversion of CO2 to organic molecules, we implemented an in vitro multienzyme system using mesophilic and thermophilic enzymes. The system, in fact, was constituted by a recombinant phosphoenolpyruvate carboxylase (PEPC) from the thermophilic cyanobacterium Thermosynechococcus elongatus, in combination with mesophilic/thermophilic bacterial carbonic anhydrases (CAs), for converting CO2 into oxaloacetate, a compound of potential utility in industrial processes. The catalytic procedure is in two steps: the conversion of CO2 into bicarbonate by CA, followed by the carboxylation of phosphoenolpyruvate with bicarbonate, catalyzed by PEPC, with formation of oxaloacetate (OAA). All tested CAs, belonging to α-, β-, and γ-CA classes, were able to increase OAA production compared to procedures when only PEPC was used. Interestingly, the efficiency of the CAs tested in OAA production was in good agreement with the kinetic parameters for the CO2 hydration reaction of these enzymes. This PEPC also revealed to be thermoactive and thermostable, and when coupled with the extremely thermostable CA from Sulphurhydrogenibium azorense (SazCA) the production of OAA was achieved even if the two enzymes were exposed to temperatures up to 60 °C, suggesting a possible role of the two coupled enzymes in biotechnological processes.
Direct catalytic benzene hydroxylation under mild reaction conditions by using a monocationic μ-nitrido-bridged iron phthalocyanine dimer with 16 peripheral methyl groups
Tanaka, Kentaro,Teoh, Chee-Ming,Toyoda, Yuka,Yamada, Yasuyuki
supporting information, p. 955 - 958 (2022/02/07)
Direct catalytic hydroxylation of benzene under mild reaction conditions proceeded efficiently in the presence of a monocationic μ-nitrido-bridged iron phthalocyanine dimer with 16 peripheral methyl groups in an acetonitrile solution with excess H2O2. Mechanistic studies suggested that the reaction was catalyzed by a high-valent iron-oxo species generated in situ. Moreover, the peripheral methyl groups of the catalyst were presumed to have enhanced the production rate of the iron-oxo species.
Bacterial flavoprotein monooxygenase YxeK salvages toxic S-(2-succino)-adducts via oxygenolytic C–S bond cleavage
Ellis, Holly R.,Kammerer, Bernd,Lagies, Simon,Matthews, Arne,Sch?nfelder, Julia,Schleicher, Erik,Stull, Frederick,Teufel, Robin
, (2021/10/06)
Thiol-containing nucleophiles such as cysteine react spontaneously with the citric acid cycle intermediate fumarate to form S-(2-succino)-adducts. In Bacillus subtilis, a salvaging pathway encoded by the yxe operon has recently been identified for the detoxification and exploitation of these compounds as sulfur sources. This route involves acetylation of S-(2-succino)cysteine to N-acetyl-2-succinocysteine, which is presumably converted to oxaloacetate and N-acetylcysteine, before a final deacetylation step affords cysteine. The critical oxidative cleavage of the C–S bond of N-acetyl-S-(2-succino)cysteine was proposed to depend on the predicted flavoprotein monooxygenase YxeK. Here, we characterize YxeK and verify its role in S-(2-succino)-adduct detoxification and sulfur metabolism. Detailed biochemical and mechanistic investigation of YxeK including 18O-isotope-labeling experiments, homology modeling, substrate specificity tests, site-directed mutagenesis, and (pre-)steady-state kinetics provides insight into the enzyme’s mechanism of action, which may involve a noncanonical flavin-N5-peroxide species for C–S bond oxygenolysis.
Interaction between Pyridoxal Hydrochloride and L-α-Asparagine in Comparison to L-α- and D-α-Aspartic Acids
Pishchugin,Tuleberdiev
, p. 49 - 54 (2021/02/26)
Abstract: The kinetics and mechanism of condensation of pyridoxal hydrochloride with L-α-asparagine, L?α- and D-α-aspartic acids are analyzed via UV spectroscopy and polarimetry. It is found that L?α?asparagine containing α-NH2 and γ-NH2/
Two-Dimensional Tin Selenide (SnSe) Nanosheets Capable of Mimicking Key Dehydrogenases in Cellular Metabolism
Gao, Meng,Wang, Zhenzhen,Zheng, Huizhen,Wang, Li,Xu, Shujuan,Liu, Xi,Li, Wei,Pan, Yanxia,Wang, Weili,Cai, Xiaoming,Wu, Ren'an,Gao, Xingfa,Li, Ruibin
supporting information, p. 3618 - 3623 (2020/02/13)
While dehydrogenases play crucial roles in tricarboxylic acid (TCA) cycle of cell metabolism, which are extensively explored for biomedical and chemical engineering uses, it is a big challenge to overcome the shortcomings (low stability and high costs) of recombinant dehydrogenases. Herein, it is shown that two-dimensional (2D) SnSe is capable of mimicking native dehydrogenases to efficiently catalyze hydrogen transfer from 1-(R)-2-(R′)-ethanol groups. In contrary to susceptible native dehydrogenases, lactic dehydrogenase (LDH) for instance, SnSe is extremely tolerant to reaction condition changes (pH, temperature, and organic solvents) and displays extraordinary reusable capability. Structure–activity analysis indicates that the single-atom structure, Sn vacancy, and hydrogen binding affinity of SnSe may be responsible for their catalytic activity. Overall, this is the first report of a 2D SnSe nanozyme to mimic key dehydrogenases in cell metabolism.
Catalytic oxidative dehydrogenation of malic acid to oxaloacetic acid
Drif, Asmaa,Pineda, Antonio,Morvan, Didier,Belliere-Baca, Virginie,De Oliveira Vigier, Karine,Jér?me, Fran?ois
supporting information, p. 4604 - 4608 (2019/09/09)
Here we report the oxidative dehydrogenation of malic acid to oxaloacetic acid, a key precursor in the fabrication of amino acids, over Pt-Bi/C catalysts. Under optimized conditions, we discovered that OAA was selectively produced with up to 60% conversion (i.e. 60% yield). The recurrent unwanted decarboxylation of OAA to pyruvic acid was circumvented by successfully conducting the catalytic reaction at 25 °C. A comparison with the classical Fenton oxidation reaction is discussed.
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 (2019/05/10)
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.
Silica Metal Oxide Vesicles Catalyze Comprehensive Prebiotic Chemistry
Mattia Bizzarri, Bruno,Botta, Lorenzo,Pérez-Valverde, Maritza Iveth,Saladino, Raffaele,Di Mauro, Ernesto,García-Ruiz, Juan Manuel
, p. 8126 - 8132 (2018/05/29)
It has recently been demonstrated that mineral self-assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth-like planets. We have s
