Gout ; diagnostic imaging ; surgery ; Humans ; Radiography ; Tartrates ; analysis ; Young Adult

AIMTo establish a resolution method for alpha-cyclohexyl mandelic acid enantiomers by enantioselective extraction and to observe the effects of all kinds of tartaric esters, pH, the concentration of D-tartaric esters and beta-cyclodextrin on the enantioselectivity.

METHODSResolution of alpha-cyclohexyl mandelic acid enantiomers by enantioselective extraction with tartaric esters and beta-cyclodextrin has been studied.

RESULTSThe distribution behavior of alpha-cyclohexyl mandelic acid enantiomers in the separation system was studied. The effects of all kinds of tartaric esters, pH, the concentration of D-tartaric esters and beta-cyclodextrin on the enantioselectivity has been examined in the two-phase.

CONCLUSIONResults showed that the complex formed by D-iso-butyl-D-tartaric ester with R enantiomer is stabler than that with S enantiomer. With the increase of pH, the partition coefficient and separation factor decreased. The concentration of beta-cyclodextrin and D-tartaric ester had visible effect on the enantioselectivity.

Esters ; Mandelic Acids ; chemistry ; Stereoisomerism ; Tartrates ; chemistry ; beta-Cyclodextrins ; chemistry

Transketolase (EC 2.2.1.1, TK) is a thiamine diphosphate-dependent enzyme that catalyzes the transfer of a two-carbon hydroxyacetyl unit with reversible C-C bond cleavage and formation. It is widely used in the production of chemicals, drug precursors, and asymmetric synthesis by cascade enzyme catalysis. In this paper, the activity of transketolase TKTA from Escherichia coli K12 on non-phosphorylated substrates was enhanced through site-directed saturation mutation and combined mutation. On this basis, the synthesis of tartaric semialdehyde was explored. The results showed that the optimal reaction temperature and pH of TKTA_M (R358I/H461S/R520Q) were 32 ℃ and 7.0, respectively. The specific activity on d-glyceraldehyde was (6.57±0.14) U/mg, which was 9.25 times higher than that of the wild type ((0.71±0.02) U/mg). Based on the characterization of TKTA_M, tartaric acid semialdehyde was synthesized with 50 mmol/L 5-keto-d-gluconate and 50 mmol/L non-phosphorylated ethanolaldehyde. The final yield of tartaric acid semialdehyde was 3.71 g with a molar conversion rate of 55.34%. Hence, the results may facilitate the preparation of l-(+)-tartaric acid from biomass, and provide an example for transketolase-catalyzed non-phosphorylated substrates.
Escherichia coli/genetics* ; Transketolase/chemistry* ; Tartrates ; Escherichia coli Proteins/genetics*

Gluconobacter oxydans converts glucose to gluconic acid and subsequently to 5-keto-D-gluconic acid (5-KGA), a precursor of industrially important L(+)-tartaric acid. To increase the yield of 5-KGA, fermentation conditions of 5-KGA production was optimized. Under the optimum medium and culture conditions in the shake flask, the highest 5-KGA production reached 19.7 g/L, increased by 43.8% after optimization. In a 5-L bioreactor, the pH was controlled at 5.5 and dissolved oxygen (DO) at 15%, 5-KGA production reached 46.0 g/L, raised at least 1.3 times than in the shake flask. Glucose feeding fermentation process was further developed, and the highest 5-KGA production of 75.5 g/L with 70% of yield was obtained, 32.0% higher than the highest reported value. Therefore, this newly developed fermentation process provided a practical and effective alternative for the commercial production of 5-KGA, and further of L(+)-tartaric acid.
Bioreactors ; Fermentation ; Gluconates ; metabolism ; Gluconobacter oxydans ; metabolism ; Glucose ; metabolism ; Industrial Microbiology ; Tartrates ; metabolism

AIMTo establish a suitable condition for extraction of phenylalanine (Phe), 5-hydroxytryptophan (5-OH-Trp) and four diastereomeric salts, (1R,2S)-ephedrine- (2S,3S)-tartaric acid, (1R,2S)-ephedrine-(2R,3R)-tartaric acid, (1S,2S)-pseudoephedrine-(2S,3S)-tartaric acid, (1S,2S)-pseudoephedrine- (2R,3R)-tartaric acid in supercritical fluid extraction and to assess the solubilities of Phe, 5-OH-Trp and the four diastereomeric salts in CO2.

METHODSSingle-pass method and HPCE.

RESULTSThe solubilities of Phe, 5-OH-Trp and the four diastereomeric salts in CO2 were determined over temperature and pressure ranges of 25-50 degrees C and 6.32-34.03 MPa respectively. The experimental results showed that the solubilities of Phe, 5-OH-Trp and the four diastereomeric salts do not increase with density of CO2. There existed a maximum in the critical region of CO2.

CONCLUSIONThe dramatically high solubilities in the pressure of 6.32-7.78 MPa show a critical behavior, which can be explained by critical characteristic through thermodynamics analysis. The results suggest that the separation of Phe, 5-OH-Trp and the four diastereomeric salts is more efficient in critical region of CO2.

5-Hydroxytryptophan ; chemistry ; Ephedrine ; chemistry ; Phenylalanine ; chemistry ; Pressure ; Solubility ; Stereoisomerism ; Tartrates ; chemistry ; Temperature

A new composite organic oscillating reaction system based on BrO₃-Ce(SO₄)₂-H₂SO₄-malonic acid/tartaric acid was proposed in this paper. On the basis of the influence of the concentration of each component on the stability and characteristic parameters of the blank system, the electrochemical fingerprints of 30 kinds of traditional Chinese medicines (TCM) were obtained. The results showed that the electrochemical fingerprint can be used for the identification of TCMs, the distinguishment of different parts and the appraisal of genuineness, which is fast, sensitive and accurate. At the same time, we explored and verified the mechanism of oscillation and the formation mechanism of TCM fingerprint.
Drugs, Chinese Herbal ; chemistry ; Electrochemical Techniques ; Malonates ; chemistry ; Medicine, Chinese Traditional ; Phytochemicals ; analysis ; Tartrates ; chemistry

In this study, we prepared various matrices of hydrogel patches and studied their cross-linking mechanism by observing their rheological properties, which could provide theoretical basis and deep technical support for further industrial development of hydrogel patch. Rheology method was used to do the amplitude scanning and single-frequency scanning for various hydrogel matrix, under the condition of oscillation mode of the rheometer. Then the linear viscoelastic region, composite modulus value, as well as changes in slope with time of the composite modulus and phase angle of various hydrogel matrix were analyzed in detail. The results showed that the stability of matrix was mainly determined by hydrogel frame; only in acidic environment, the cross-linking reaction between cross-linker and hydrogel frame can occur; elasticity of matrix can be decreased by organic acid and the effect level was related to the ratio of the number of carboxyl and hydroxyl (-COO(-)/-OH) in adjusters: if the ratio was not equal, the higher -COO(-)/-OH in adjusters would be the less elasticity of matrix decreased; the cross-linking speed of matrix was determined by adjuster, the cross-linking speed of matrix contain different adjusters was ranged in following order: matrix containing tartaric acid > matrix containing lactic acid > matrix containing malic acid > matrix containing citric acid; the cross-linking speed of matrix was not uniform in the whole cross-linking process.
Citric Acid ; chemistry ; Cross-Linking Reagents ; chemistry ; Hydrogels ; chemistry ; Lactic Acid ; chemistry ; Malates ; chemistry ; Rheology ; Tartrates ; chemistry ; Viscosity

The cis-epoxysuccinate hydrolase (CESH) from Rhizobium strain BK-20 is the key enzyme for L(+)-tartaric acid production. To establish a highly efficient and stable production process, we first optimized the enzyme production from Rhizobium strain BK-20, and then developed an immobilized cell-culture process for sustained production of L(+)-tartaric acid. The enzyme activity of free cells reached (3 498.0 +/- 142.6) U/g, and increased by 643% after optimization. The enzyme activity of immobilized cells reached (2 817.2 +/- 226.7) U/g, under the optimal condition with sodium alginate as carrier, cell concentration at 10% (W/V) and gel concentration at 1.5% (W/V). The immobilized cells preserved high enzyme activity and normal structure after 10 repeated batches. The conversion rate of the substrate was more than 98%, indicating its excellent production stability.
Alginates ; chemistry ; Cells, Immobilized ; Glucuronic Acid ; chemistry ; Hexuronic Acids ; chemistry ; Hydrolases ; metabolism ; Rhizobium ; enzymology ; metabolism ; Tartrates ; metabolism

The L(+)-form of tartaric acid (L(+)-TA) exists extensively in nature, and is widely used in the food, chemical, textile, building, and pharmaceutical industries (Su et al., 2001). The main method for L(+)-TA production is microbial transformation by cis-epoxysuccinate hydrolase (CESH), which can catalyze the asymmetric hydrolysis of cis-epoxysuccinic acid or its salts to TA or tartrate (Bao et al., 2019). Seventeen species containing CESH have been isolated so far. However, most species for L(+)-TA production have been reported from bacteria (Xuan and Feng, 2019). The only fungus isolated from soil by our lab recently, that could be used as catalyst for the process under acidic condition, is Aspergillus niger WH-2 (Bao et al., 2020). In order to find strains with new characteristics, this study attempted to isolate a new CESH source from fungi and investigate its application value.
Aspergillus niger/metabolism* ; Biomass ; Catalysis ; Fermentation ; Hydrogen-Ion Concentration ; Hydrolases/chemistry* ; Hydrolysis ; Industrial Microbiology ; Magnetic Resonance Spectroscopy ; Penicillium/metabolism* ; Phylogeny ; Soil ; Species Specificity ; Stereoisomerism ; Tartrates/chemistry* ; Temperature ; Textiles

AIMTo evaluate the effects of an array of additives on drug release from double-layered poly(lactic-co-glycolic acid) (PLGA) matrices.

METHODSAdditives differing in molecular size, hydrophilicity and steric configuration were selected for this study. An anti-proliferative 2-aminochromone, U-86983 (U-86, Pharmacia and Upjohn), was used as a model agent because of our interest in investigating local drug delivery systems for the inhibition of restenosis.

RESULTSIn vitro release of U-86 PLGA matrices without additive showed a typical biphasic release kinetics, i.e. a slow diffusion release (Phase I) followed by a fast erosion-mediated release (Phase II). The water-soluble additives in PLGA matrices changed the biphasic release pattern to a near monophasic profile by increasing the release of the Phase I. Increasing the ratio of additives to PLGA in matrices caused a significant increase in U-86 release rates. A high molecular weight water-soluble additive, Pluronic F127, resulted in a matrix showing perfect zero-order release kinetics. The morphologic evaluation of matrices using scanning electron microscopy indicated that the water-soluble additives were leachable and thus generated a highly porous structure in the matrices. Conclusion Water-solubility, molecular size and steric configuration of additives are the important determinants in generating various types of pore structures in polymer matrix which in turn affect the release mechanism and release kinetics.

Biocompatible Materials ; chemistry ; Chromones ; administration & dosage ; chemistry ; Delayed-Action Preparations ; Drug Carriers ; Drug Delivery Systems ; Excipients ; chemistry ; Lactic Acid ; chemistry ; Molecular Weight ; Morpholines ; administration & dosage ; chemistry ; Pharmacokinetics ; Poloxamer ; chemistry ; Polyglycolic Acid ; chemistry ; Polymers ; chemistry ; Tartrates ; chemistry