- Cross-linked LDH crystals for lactate synthesis coupled to electroenzymatic regeneration of NADH
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Lactate dehydrogenase (LDH) was crystallized from concentrated ammonium sulfate solution and cross-linked with glutaraldehyde to afford long-lived enzymatically active cross-linked crystals (LDH-CLC). The crystals were employed in an electrolytic cell for lactate production from pyruvate, in which the cathode consisted of a carbon electrode containing a coating of lipoamide dehydrogenase (LiDH) immobilized with methyl viologen under a Nafion membrane. This cell was more effective than a similar cell containing LDH in soluble form. An even greater improvement in performance was achieved by chemically binding a viologen derivative to the LiDH and using an electrode based on this modified enzyme in a cell containing LDH-CLC. The activity of the LDH-CLC is much less sensitive to pH than that of the soluble enzyme.
- Sobolov, Susan B.,Leonida, Mihaela Draganoiu,Bartoszko-Malik, Anita,Voivodov, Kamen I.,McKinney, Frank,Kim, Jason,Fry, Albert J.
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- Carbon as a Simple Support for Redox Biocatalysis in Continuous Flow
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A continuous packed bed reactor for NADH-dependent biocatalysis using enzymes co-immobilized on a simple carbon support was optimized to 100% conversion in a residence time of 30 min. Conversion of pyruvate to lactate was achieved by co-immobilized lactate dehydrogenase and formate dehydrogenase, providing in situ cofactor recycling. Other metrics were also considered as optimization targets, such as low E factors between 2.5-11 and space-time yields of up to 22.9 g L-1 h-1. The long-term stability of the biocatalytic reactor was also demonstrated, with full conversion maintained over more than 30 h of continuous operation.
- Poznansky, Barnabas,Reeve, Holly A.,Thompson, Lisa A.,Vincent, Kylie A.,Warren, Sarah A.
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- NOVEL STING AGONISTS
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The present invention provides compounds of Formula I′: wherein , W, X, Y, Z, Z1, Z2, R1, R2, R3, R4 and R5 are as defined herein, or a stereoisomer, tautomer, pharmaceutically acceptable salt, prodrug ester or solvate form thereof, wherein all of the variables are as defined herein. These compounds are effective at modulating the STING protein and thus can be used as medicaments for treating or preventing disorders affected by the agonism of STING.
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Paragraph 0756; 0761; 0762
(2020/05/14)
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- Enantioselective catabolism of racemic serine: Preparation of d-serine using whole cells of Fusobacterium nucleatum
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Incubation of racemic serine with the anaerobic bacterium Fusobacterium nucleatum yielded d-serine in high enantiomeric excess (>95%). Selective degradation of the l-amino acid was most efficient when F. nucleatum was resuspended in a buffer at high cell densities (ca. 50-100 g damp cells/L); a single incubation effectively removed almost all l-serine from racemic mixtures at initial concentrations up to 800 mM, the solubility limit. The product d-amino acid was separated from the metabolic end-products (acetate, butyrate and lactate) and buffer components by a single cation-exchange step. After recrystallization, 83% of the d-serine in the initial racemate was recovered with >99% ee (HPLC) and 98% purity (HPLC). This anaerobic microbial approach provides a viable complementary method for generating d-serine, a valuable chiral starting material for chemical synthesis.
- Ramezani, Mohammad,White, Robert L.
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experimental part
p. 1473 - 1478
(2011/11/12)
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- Effect of high-pressure processing on activity and structure of alkaline phosphatase and lactate dehydrogenase in buffer and milk
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Changes in the activity and structure of alkaline phosphatase (ALP) and L-lactate dehydrogenase (LDH) were investigated after high pressure processing (HPP). HPP treatments (206-620 MPa for 6 and 12 min) were applied to ALP and LDH prepared in buffer, fat-free milk, and 2% fat milk. Enzyme activities were measured using enzymatic assays, and changes in structure were investigated using far-ultraviolet circular dichroism (CD) spectroscopy and dynamic light scattetering (DLS). Kinetic data indicated that the activity of ALP was not affected after 6 min of pressure treatments (206-620 MPa), regardless of the medium in which the enzyme was prepared. Increasing the processing time to 12 min did significantly reduce the activity of ALP at 620 MPa (P 0.001). However, even the lowest HPP treatment of 206 MPa induced a reduction in LDH activity, and the course of reduction increased with HPP treatment until complete inactivation at 482, 515, and 620 MPa. CD data demonstrated a partial change in the secondary structure of ALP at 620 MPa, whereas the structure of LDH showed gradual denaturation after exposure at 206 MPa for 6 min, leading to a random coil structure at both 515 and 620 MPa. DLS results indicated aggregation of ALP only at HPP treatment of 206 MPa and not above and enzyme precipitation as well as aggregation at 345, 415, 482, and 515 MPa. The loss of LDH activity with increasing pressure and time treatment was due to the combined effects of denaturation and aggregation.
- Kouassi, Gilles K.,Anantheswaran, Ramaswamy C.,Knabel, Stephen J.,Floros, John D.
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p. 9520 - 9529
(2008/03/14)
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- Menthyl lactate process
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A simple, high-yield process for making menthyl lactate (ML) is disclosed. Menthol and lactic acid react to produce a mixture comprising menthyl lactate and one or more higher lactoyl esters of ML. Hydrolysis of the esterification mixture follows in the presence of aqueous base under conditions effective to convert the higher lactoyl esters to menthyl lactate. Coincidentally, the conditions minimize hydrolysis of menthyl lactate to menthol, thereby maximizing the overall yield of ML.
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Page/Page column 5-8
(2008/06/13)
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