113-24-6Relevant academic research and scientific papers
Chemical transformations of the condensation products of pyridoxal with L-α-alanine and D-α-alanine
Pishchugin,Tuleberdiev
, p. 117 - 120 (2009)
The kinetics and mechanism of the reactions of pyridoxal with L- and D-α-alanine were studied. Under comparable conditions, the condensation of L- and D-α-alanines with pyridoxal includes three kinetically different steps. The first fast step is addition
The Ala95-to-Gly substitution in Aerococcus viridans l -lactate oxidase revisited - Structural consequences at the catalytic site and effect on reactivity with O2 and other electron acceptors
Stoisser, Thomas,Rainer, Daniela,Leitgeb, Stefan,Wilson, David K.,Nidetzky, Bernd
, p. 562 - 578 (2015)
Aerococcus viridansl-lactate oxidase (avLOX) is a biotechnologically important flavoenzyme that catalyzes the conversion of l-lactate and O2 into pyruvate and H2O2. The enzymatic reaction underlies different biosensor applications of avLOX for blood l-lactate determination. The ability of avLOX to replace O2 with other electron acceptors such as 2,6-dichlorophenol-indophenol (DCIP) allows the possiblity of analytical and practical applications. The A95G variant of avLOX was previously shown to exhibit lowered reactivity with O2 compared to wild-type enzyme and therefore was employed in a detailed investigation with respect to the specificity for different electron acceptor substrates. From stopped-flow experiments performed at 20 °C (pH 6.5), we determined that the A95G variant (fully reduced by l-lactate) was approximately three-fold more reactive towards DCIP (1.0 ± 0.1 × 106 M-1·s-1) than O2, whereas avLOX wild-type under the same conditions was 14-fold more reactive towards O2 (1.8 ± 0.1 × 106 m-1·s-1) than DCIP. Substituted 1,4-benzoquinones were up to five-fold better electron acceptors for reaction with l-lactate-reduced A95G variant than wild-type. A 1.65-? crystal structure of oxidized A95G variant bound with pyruvate was determined and revealed that the steric volume created by removal of the methyl side chain of Ala95 and a slight additional shift in the main chain at position Gly95 together enable the accomodation of a new active-site water molecule within hydrogen-bond distance to the N5 of the FMN cofactor. The increased steric volume available in the active site allows the A95G variant to exhibit a similar trend with the related glycolate oxidase in electron acceptor substrate specificities, despite the latter containing an alanine at the analogous position.
Comparison of two metal-dependent pyruvate aldolases related by convergent evolution: Substrate specificity, kinetic mechanism, and substrate channeling
Wang, Weijun,Baker, Perrin,Seah, Stephen Y. K.
, p. 3774 - 3782 (2010)
HpaI and BphI are two pyruvate class II aldolases found in aromatic meta-cleavage degradation pathways that catalyze similar reactions but are not related in sequence. Steady-state kinetic analysis of the aldol addition reactions and product inhibition assays showed that HpaI exhibits a rapid equilibrium random order mechanism while BphI exhibits a compulsory order mechanism, with pyruvate binding first. Both aldolases are able to utilize aldehyde acceptors two to five carbons in length; however, HpaI showed broader specificity and had a preference for aldehydes containing longer linear alkyl chains or C2-OH substitutions. Both enzymes were able to bind 2-keto acids larger than pyruvate, but only HpaI was able to utilize both pyruvate and 2-ketobutanoate as carbonyl donors in the aldol addition reaction. HpaI lacks stereospecific control producing racemic mixtures of 4-hydroxy-2-oxopentanoate (HOPA) from pyruvate and acetaldehyde while BphI synthesizes only (4S)-HOPA. BphI is also able to utilize acetaldehyde produced by the reduction of acetyl-CoA catalyzed by the associated aldehyde dehydrogenase, BphJ. This aldehyde was directly channeled from the dehydrogenase to the aldolase active sites, with an efficiency of 84%. Furthermore, the BphJ reductive deacylation reaction increased 4-fold when BphI was catalyzing the aldol addition reaction. Therefore, the BphI-BphJ enzyme complex exhibits unique bidirectionality in substrate channeling and allosteric activation.
Alcohol oxidation catalysed by Ru(VI) in the presence of alkaline hexacyanoferrate(III)
Poblete, Francisco J.,Corrochano, Pablo
, p. 1088 - 1092 (2010)
The oxidation of sodium lactate, 2-methyl-2,4-pentanediol, 2,4-butanediol, 2-butanol and 2-propanol upon treatment with alkaline hexacyanoferrate(III) using a Ru(VI) catalyst is highly effective for the oxidation of alcohols by Fe(CN)63-. The reaction mechanism proposed involves the oxidation of the alcohol by the catalyst, a process that occurs through the formation of a substrate-catalyst complex. The decomposition of this complex yields Ru(IV) and a carbocation (owing to a hydride transfer from the α-C-H bond of the alcohol to the oxoligand of ruthenium). The role of the co-oxidant, hexacyanoferrate(III), is to regenerate the catalyst. In the oxidation reactions, the rate constants for complex decomposition and catalyst regeneration have been determined and a comparative study of the structure versus reactivity has been carried out. Copyright
A comparative study of the enolization of pyruvate and the reversible dehydration of pyruvate hydrate
Damitio,Smith,Meany,Pocker
, p. 3081 - 3087 (1992)
The enolization of pyruvate and the reversible dehydration of pyruvate hydrate were studied at 25.0°C using spectrophotometric methods. The enolization of pyruvate was followed at 353 nm by monitoring the rate of uptake of triiodide ion. The dehydration of pyruvate hydrate was initiated by introducing small quantities of preacidified solutions of pyruvic acid containing, at the kinetic zero, ca. 60% of the hydrate into buffer solutions. A decrease in absorbance at 325 nm took place as the reaction progressed to a final solution composition of 6% hydrate. The reactions were studied in acetate, MES, phosphate, arsenate, imidazole, 1-methylimidazole, HEPES, Tris, and borate buffers. The dehydration of pyruvate hydrate was found to be sensitive toward general-acid and general-base catalysis, while the enolization of pyruvate was catalyzed only by the basic components of the buffers studied. The corresponding rate coefficients were determined for the acidic and basic catalysts, and taking into account the appropriate statistical correction factors associated with the capacity of the catalysts to donate and accept protons, Br?nsted plots were constructed. Br?nsted coefficients were determined for enolization (β = 0.47) and for dehydration (α = 0.54, β= 0.52). While relatively normal catalytic behavior was observed for the enolization of pyruvate, deviations for the dehydration of hydrated pyruvate were noted. Analysis of these deviations, in light of a comparison of the relative magnitude of the catalytic rate coefficients for the reversible hydrations of other carbonyl compounds, suggests the possible contribution of a general-base catalytic path involving the intramolecular participation of the carboxylate group of hydrated pyruvate. The data are also considered in terms of the possible roles the rates of interconversion and positions of equilibria between keto, enol, and hydrated species may play in the physiological reactions of pyruvate. Finally, the Br?nsted analysis provides the necessary basis for a comparison of the relative susceptibilities of the many substrates of carbonic anhydrase II including pyruvate hydrate.
Preparation method of sodium pyruvate
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Paragraph 0033-0122, (2018/07/30)
The invention relates to the field of preparation of sodium pyruvate, in particular to a preparation method of sodium pyruvate. The preparation method comprises the following steps that ethyl lactateis subjected to an oxidizing reaction under existing of a catalyst, and sodium pyruvate is obtained after hydrolyzation and neutralization are conducted, wherein the catalyst is one or more of 2,2,6,6-tetramethylpiperidine oxide, 9-azabicyclo[3.3.1]nonane-N-oxy-compound, 9-azabicyclo[3.3.1]nonane-3-ene-N-oxy-compound, 4,2,2,6,6-tetrametylpiperidine oxide and 4-amino-2,2,6,6-tetrametylpiperidine oxide. Compared with the existing commonly used bromine, the prepared method of sodium pyruvate improves the reaction rate of oxidization, and in the oxidization reaction process, the reaction is more steady and safer. In addition, a by-product, namely yellow oily matter is reduced, and post-treatment is easier as well.
Discovery and characterization of a thermostable D-lactate dehydrogenase from Lactobacillus jensenii through genome mining
Jun, Chanha,Sa, Young Seung,Gu, Sol-A,Joo, Jeong Chan,Kim, Seil,Kim, Kyung-Jin,Kim, Yong Hwan
, p. 109 - 117 (2013/04/10)
The demand on thermostable D-lactate dehydrogenases (d-LDH) has been increased for d-lactic acid production but thermostable d-DLHs with industrially applicable activity were not much explored. To identify a thermostable d-LDH, three d-LDHs from different Lactobacillus jensenii strains were screened by genome mining and then expressed in Escherichia coli. One of the three d-LDHs (d-LDH3) exhibited higher optimal reaction temperature (50 °C) than the others. The T5010 value of this thermostable d-LDH3 was 48.3 °C, much higher than the T5010 values of the others (42.7 and 42.9 °C) and that of a commercial D-lactate dehydrogenase (41.2 °C). The Tm values were 48.6, 45.7 and 55.7 °C for the three d-LDHs, respectively. In addition, kinetic parameter (k cat/Km) of d-LDH3 for pyruvate reduction was estimated to be almost 150 times higher than that for lactate oxidation at pH 8.0 and 25 °C, implying that D-lactate production from pyruvate is highly favored. These superior thermal and kinetic features would make the d-LDH3 characterized in this study a good candidate for the microbial production of D-lactate at high temperature from glucose if it is genetically introduced to lactate producing microbial.
Rational design of stereoselectivity in the class II pyruvate aldolase BphI
Baker, Perrin,Seah, Stephen Y. K.
scheme or table, p. 507 - 513 (2012/03/07)
BphI, a pyruvate-specific class II aldolase, catalyzes the reversible carbon-carbon bond formation of 4-hydroxy-2-oxoacids up to eight carbons in length. During the aldol addition catalyzed by BphI, the S-configured stereogenic center at C4 is created via attack of a pyruvate enolate intermediate on the si face of the aldehyde carbonyl of acetaldehyde to form 4(S)-hydroxy-2-oxopentanoate. Replacement of a Leu-87 residue within the active site of the enzyme with polar asparagine and bulky tryptophan led to enzymes with no detectable aldolase activity. These variants retained decarboxylase activity for the smaller oxaloacetate substrate, which is not inhibited by excess 4-hydroxy-2-oxopentanoate, confirming the results from molecular modeling that Leu-87 interacts with the C4-methyl of 4(S)-hydroxy-2-oxoacids. Double variants L87N;Y290F and L87W;Y290F were constructed to enable the binding of 4(R)-hydroxy-2-oxoacids by relieving the steric hindrance between the 5-methyl group of these compounds and the hydroxyl substituent on the phenyl ring of Tyr-290. The resultant enzymes were shown to exclusively utilize only 4(R)- and not 4(S)-hydroxy-2-oxopentanoate as the substrate. Polarimetric analysis confirmed that the double variants are able to synthesize 4-hydroxy-2-oxoacids up to eight carbons in length, which were the opposite stereoisomer compared to those produced by the wild-type enzyme. Overall the kcat/K m values for pyruvate and aldehydes in the aldol addition reactions were affected 10-fold in the double variants relative to the wild-type enzyme. Thus, stereocomplementary class II pyruvate aldolases are now available to create chiral 4-hydroxy-2-oxoacid skeletons as synthons for organic reactions.
A rationally designed aldolase foldamer
Mueller, Manuel M.,Windsor, Matthew A.,Pomerantz, William C.,Gellman, Samuel H.,Hilvert, Donald
supporting information; experimental part, p. 922 - 925 (2009/05/15)
(Chemical Equation Presented) Neatly folded: A decameric β-peptide shows enzyme-like catalytic properties. The foldamer, which bears a terminal heptanoyl unit and displays a thermostable helical structure with an array of ammonium-group side chains, accel
DIALYSIS SOLUTIONS CONTAINING PYROPHOSPHATES
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, (2009/04/24)
Dialysis solutions comprising pyrophosphates and methods of making and using the dialysis solutions are provided. In an embodiment, the present disclosure provides a dialysis solution comprising a stable and therapeutically effective amount of pyrophosphate. The dialysis solution can be sterilized, for example, using a technique such as autoclave, steam, high pressure, ultra-violet, filtration or combination thereof. The dialysis solution can be in the form of a concentrate.
