69-53-4Relevant academic research and scientific papers
Penicillin Acylase Catalysed Synthesis of Ampicillin in Hydrophilic Organic Solvents
Van Langen, Luuk M.,Oosthoek, Natasja H. P.,Van Rantwijk, Fred,Sheldon, Roger A.
, p. 797 - 801 (2003)
Penicillin acylase (EC 3.5.1.11) from Alcaligenes faecalis, immobilised as a cross-linked enzyme aggregate (CLEA), catalysed the synthesis of ampicillin in water-miscible organic solvents at low water concentrations. Below 4% water (v/v) no reaction was observed, showing the crucial role of water in maintaining the activity of penicillin acylase. The initial value of S/H was strongly affected by the nature of the solvent, but the effect of the water content was slight in the studied range of 4 to 15%. A reaction in acetonitrile containing 8% water afforded ampicillin in up to 86% yield.
Penicillin Acylase-Catalyzed Solid-State Ampicillin Synthesis
Youshko,Svedas
, p. 894 - 898 (2002)
The ability of immobilized penicillin acylase from E. coli to retain a remarkable catalytic activity in solid-state systems has been demonstrated. Stabilization of immobilized penicillin acylase by inorganic salt hydrates allowed us to exploit nearly the whole catalytic activity of the enzyme at a very low water content. Using this technique, enzymatic synthesis of ampicillin in solid-state systems was performed with high yields (up to 70% starting from equimolar mixture of reagents) and rates comparable to the corresponding values in homogeneous solutions and heterogeneous systems, "aqueous solution-precipitate". Peculiarities of the enzymatic solid-state acyl transfer process, such as absence of the clear-cut maximum on the ampicillin accumulation curves and dependence of the synthetic efficiency on the enzyme loading, have been observed. The space-time yield of solid-state enzymatic ampicillin synthesis was shown to be up to ten times higher compared to the homogeneous solutions and heterogeneous "aqueous solution-precipitate" systems.
Efficient enzymatic synthesis of ampicillin using mutant Penicillin G acylase with bio-based solvent glycerol
Deng, Senwen,Ma, Xiaoqiang,Sun, Ming,Wei, Dongzhi,Su, Erzheng
, p. 31 - 34 (2016)
To fulfill the industry demand of ampicillin enzymatic synthesis, immobilized mutant Penicillin G acylase and bio-based solvent glycerol were employed at high substrate concentration and low acyl donor/nucleophile ratio. After process optimization, good yield and low operation costs were achieved.
An efficient synthesis of ampicillin on magnetically separable immobilized penicillin G acylase
Xue, Ping,Song, Xiao Dan,Cao, Xue Rong
, p. 765 - 768 (2010)
Penicillin G acylase (PGA) was immobilized on the magnetic hydrophilic polymer microspheres with average pore size of 17.1 nm, specific surface area of 128.2 m2/g and saturate magnetization of 6.4 emu/g. The 96.7% ampicillin yield with 1.60 of the synthesis/hydrolysis (S/H) ratio from 6-aminopenicillanic acid (6-APA) and D-(-)-alpha-phenylglycine methyl ester (D-PGME) can be achieved using the resultant magnetic biocatalyst in ethylene glycol, where only 82.1% yield with 1.40 of the S/H ratio was obtained using the free PGA under the identical reaction conditions. The immobilized PGA can be separated magnetically and recycled for five times without obvious loss of its catalytic activity.
A high-throughput pH-based colorimetric assay: application focus on alpha/beta hydrolases
Paye, Mariétou F.,Rose, Harrison B.,Robbins, John M.,Yunda, Diana A.,Cho, Seonggeon,Bommarius, Andreas S.
, p. 80 - 90 (2018/03/24)
Research involving α/β hydrolases, including α-amino acid ester hydrolase and cocaine esterase, has been limited by the lack of an online high throughput screening assay. The development of a high throughput screening assay capable of detecting α/β hydrolase activity toward specific substrates and/or chemical reactions (e.g., hydrolysis in lieu of amidase activity and/or synthesis instead of thioesterase activity) is of interest in a broad set of scientific questions and applications. Here we present a general framework for pH-based colorimetric assays, as well as the mathematical considerations necessary to estimate de novo the experimental response required to assign a ‘hit’ or a ‘miss,’ in the absence of experimental standard curves. This combination is valuable for screening the hydrolysis and synthesis activity of α/β hydrolases on a variety of substrates, and produces data comparable to the current standard technique involving High Performance Liquid Chromatography (HPLC). In contrast to HPLC, this assay enables screening experiments to be performed with greater efficiency.
IMMORTALIZED STEM CELL, COMPOSITIONS, PREPARATIONS AND USES THEREOF
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, (2018/01/14)
The purpose of the present invention is to provide immortalized stem cells, which produce a growth factor capable of regenerating various kinds of tissues that have been damaged by a variety of causes, and a method for producing the aforesaid immortalized stem cells. Another purpose is to provide a medicinal composition and a medicinal preparation for restoring damaged tissues, and a method for the percutaneous absorption of a culture supernatant. Provided are immortalized stem cells that are obtained by isolating stem cells selected from the group consisting of mammalian mesenchymal cells, an embryo at the early stage of the development and somatic cells, first culturing the cells to give first stage culture cells, transferring four kinds of genes into the first stage culture cells to give transgenic cells, and selecting the desired immortalized stem cells from among the transgenic cells using the expression of STRO-1 as an index.
Amino ester hydrolase from Xanthomonas campestris pv. campestris, ATCC 33913 for enzymatic synthesis of ampicillin
Blum, Janna K.,Bommarius, Andreas S.
experimental part, p. 21 - 28 (2010/12/19)
α-Amino ester hydrolases (AEH) are a small class of proteins, which are highly specific for hydrolysis or synthesis of α-amino containing amides and esters including β-lactam antibiotics such as ampicillin, amoxicillin, and cephalexin. A BLAST search revealed the sequence of a putative glutaryl 7-aminocephalosporanic acid (GL-7-ACA) acylase 93% identical to a known AEH from Xanthomonas citri. The gene, termed gaa, was cloned from the genomic DNA of Xanthomonas campestris pv. campestris sp. strain ATCC 33913 and the corresponding protein was expressed into Escherichia coli. The purified protein was able to perform both hydrolysis and synthesis of a variety of α-amino β-lactam antibiotics including (R)-ampicillin and cephalexin, with optimal ampicillin hydrolytic activity at 25 °C and pH 6.8, with kinetic parameters of kcat of 72.5 s-1 and KM of 1.1 mM. The synthesis parameters α, βo, and γ for ampicillin, determined here first for this class of proteins, are α = 0.25, βo = 42.8 M-1, and γ = 0.23, and demonstrate the excellent synthetic potential of these enzymes. An extensive study of site-directed mutations around the binding pocket of X. campestris pv. campestris AEH strongly suggests that mutation of almost any first-shell amino acid residues around the active site leads to inactive enzyme, including Y82, Y175, D207, D208, W209, Y222, and E309, in addition to those residues forming the catalytic triad, S174, H340, and D307.
Apparatus And Methods For Delivering A Plurality Of Medicaments For Management Of Co-Morbid Diseases, Illnesses Or Conditions
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, (2010/09/07)
A method and apparatus for delivering a plurality of medicaments in a single delivery vehicle for the management of co-morbid diseases, illnesses and conditions. The present invention provides a novel delivery process for many medicaments. Medicaments may be encapsulated and stored separately within a larger capsule until the time of ingestion, consumption, or the like. Benefits of the present invention include maintaining separation of distinct ingredients within a single capsule and the capability to control the time release of multiple ingredients within the capsule.
Combinatorial improvement of bifunctional drug properties
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, (2009/07/02)
A method is provided for improving at least one pharmacokinetic property and maintaining or improving affinity of a therapeutic upon administration to a host. In the method, one administers to the host an effective amount of a bifunctional compound of less than about 5000 Daltons comprising the therapeutic or an active derivative, fragment or analog thereof and a recruiter ligand moiety. The recruiter ligand moiety binds to at least one biomoiety. The bifunctional compound has at least one modulated pharmacokinetic property upon administration to the host and equivalent or greater affinity for a target of the therapeutic as compared to a free drug control that comprises the therapeutic. In addition, the overall drug efficacy is improved by the steric bulk of the bifunctional complexed with the recruited biomoiety.
Method of using deuterated calcium channel blockers
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, (2008/06/13)
Therapeutic methods and compositions using deuterated enriched 2-[(2-aminoethoxy)methyl]-4-(2-chlorophenyl)-1,4-dihydro-6-methyl-3,5-pyridinedicarboxylic acid 3-ethyl 5-methyl ester and other deuterated dihydropyridine compounds are described. The deuterated compounds exhibit enhanced efficacy in blocking calcium channels over non-deuterated dihydropyridines.
