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Magneto‐Archimedes levitation (MagLev) enables the separation of powdered mixtures of illicit drugs (cocaine, methamphetamine, heroin, fentanyl, and its analogues), adulterants, and diluents based on density, and allows the presumptive identification of individual components. Small samples (mass <50 mg), with low concentrations of illicit drugs, present a particular challenge to analysis for forensic chemists. The MagLev device, a cuvette containing a solution of paramagnetic gadolinium(III) chelate in a non‐polar solvent, placed between two like‐poles‐facing NdFeB magnets, allowed separation of seven relevant compounds simultaneously. In particular, initial separation with MagLev, followed by characterization by FTIR‐ATR, enabled identification of fentanyl in a sample of fentanyl‐laced heroin (1.3 wt % fentanyl, 2.6 wt % heroin, and 96.1 wt % lactose). MagLev allows identification of unknown powders in mixtures and enables confirmatory identification based on structure‐specific techniques. [ABSTRACT FROM AUTHOR]

Biomolecular recognition can be stubborn; changes in the structures of associating molecules, or the environments in which they associate, often yield compensating changes in enthalpies and entropies of binding and no net change in affinities. This phenomenon-termed enthalpy/entropy (H/S) compensation-hinders efforts in biomolecular design, and its incidence-often a surprise to experimentalists-makes interactions between biomolecules difficult to predict. Although characterizing H/S compensation requires experimental care, it is unquestionably a real phenomenon that has, from an engineering perspective, useful physical origins. Studying H/S compensation can help illuminate the still-murky roles of water and dynamics in biomolecular recognition and self-assembly. This review summarizes known sources of H/ S compensation (real and perceived) and lays out a conceptual framework for understanding and dissecting-and, perhaps, avoiding or exploiting-this phenomenon in biophysical systems. [ABSTRACT FROM AUTHOR]

This paper describes the measurement and analysis of in vivo activity and stability of cyclohexanone monooxygenase from Acinetobacter sp. NCIMB 9871 (CHMO), a model Baeyer-Villiger monooxygenase, in the recombinant host Escherichia coli. This enzyme was often described as poorly stable in vitro, and has recently been found to deactivate rapidly in the absence of its essential cofactors and antioxidants. Its stability in vivo was scarcely studied, so far. Under conditions common for the overexpression of CHMO we investigated the ability of the host to support these properties using metabolomics. Our results showed that E. coli failed to provide the intracellular levels of cofactors required to functionally stabilize the enzyme, although the biocatalyst was produced in high concentration, and was invariably detected after protein synthesis had stopped. We thus infer that biotechnological applications of CHMO with this host relied on a residual activity of approximately 5-10%. Other microorganisms might offer a more efficient solution for recombinant production of CHMO and related enzymes. [ABSTRACT FROM AUTHOR]

We describe the development of a kinetic model for the simulation and optimization of an in vivo redox cascade in E. coli in which a combination of an alcohol dehydrogenase, an enoate reductase, and a Baeyer-Villiger monooxygenase is used for the synthesis of lactones. The model was used to estimate the concentrations of active enzyme in the sequential biotransformations to identify bottlenecks together with their reasons and how to overcome them. We estimated adapted Michaelis-Menten parameters from in vitro experiments with isolated enzymes and used these values to simulate the change in the concentrations of intermediates and products during the in vivo cascade reactions. Remarkably, the model indicated that the fastest enzyme was rate-determining because of the unexpectedly low concentration of the active form, which opens up reversible reaction channels towards byproducts. We also provide substantial experimental evidence that a low intracellular concentration of flavin and nicotinamide cofactors drastically decreased the performance of the in vivo cascade drastically. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper describes the development of a biocatalytic process on the multi-dozen gram scale for the synthesis of a precursor to Nylon-9, a specialty polyamide. Such materials are growing in demand, but their corresponding monomers are often difficult to synthesize, giving rise to biocatalytic approaches. Here, we implemented cyclopentadecanone monooxygenase as an Escherichia coli whole-cell biocatalyst in a defined medium, together with a substrate feeding-product removal concept, and an optimized downstream processing (DSP). A previously described hazardous peracid-mediated oxidation was thus replaced with a safe and scalable protocol, using aerial oxygen as oxidant, and water as reaction solvent. The engineered process converted 42 g (0.28 mol) starting material ketone to the corresponding lactone with an isolated yield of 70% (33 g), after highly efficient DSP with 95% recovery of the converted material, translating to a volumetric yield of 8 g pure product per liter. Biotechnol. Bioeng. 2017;114: 1670-1678. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

This paper describes the stabilization of flavin-dependent monooxygenases under reaction conditions, using an engineered formulation of additives (the natural cofactors NADPH and FAD, and superoxide dismutase and catalase as catalytic antioxidants). This way, a 103- to 104-fold increase of the half-life was reached without resource-intensive directed evolution or structure-dependent protein engineering methods. The stabilized enzymes are highly valued for their synthetic potential in biotechnology and medicinal chemistry (enantioselective sulfur, nitrogen and Baeyer-Villiger oxidations; oxidative human metabolism), but widespread application was so far hindered by their notorious fragility. Our technology immediately enables their use, does not require structural knowledge of the biocatalyst, and creates a strong basis for the targeted development of improved variants by mutagenesis. [ABSTRACT FROM AUTHOR]

Herein we highlight recent findings on the importance of water networks in proteins, and their redesign and reconfiguration as a new engineering strategy to generate enzymes with modulated binding affinity and improved catalytic versatility. Traditionally, enzyme engineering and drug design have focused on tailoring direct and favorable interactions between protein surfaces and ligands/transition states to achieve stronger binding, or an accelerated manufacturing of medicines, biofuels, fine chemicals and materials. In contrast, the opportunity to relocate water molecules in solvated binding pockets by protein design to improve overall energetics remains essentially unexplored, and fundamental understanding of the elusive processes involved is poor. Rewiring water networks in protein interiors impacts binding affinity, catalysis and the thermodynamic signature of biochemical processes through dynamic mechanisms, and thus has great potential to enhance binding specificity, accelerate catalysis and provide new reaction mechanisms and chemistry, that were not yet explored in nature. [ABSTRACT FROM AUTHOR]

We report herein the first total synthesis of piperenol B, a polyoxygenated cyclohexene derivative with reported pharmacological activity isolated from Piper cubeb. The chiral building block for this synthetic approach is derived from microbial cis-ipso, ortho-dihydroxylation of sodium benzoate, which was optimized to the multi-ten-gram scale by reaction medium engineering. Final-stage deprotection of an acetonide was investigated in detail, leading to an efficient eight-step protocol for the synthesis of piperenol B with a total yield of 10 %. Most importantly, the previously assigned absolute configuration of piperenol B was revised and unequivocally established by 2D NMR analysis and the Mosher's ester method. [ABSTRACT FROM AUTHOR]

Baeyer–Villiger monooxygenases catalyze the energetically challenging oxidation of levulinates (4-oxopentanoates) to 3-hydroxypropionic acid (3-HPA) derivates under ambient conditions, replacing propellant-grade H2O2 with aerial oxygen as the oxidant. This reaction enables a new pathway to a platform for chemical 3-HPA, an important intermediate in the non-petrol based production of a variety of bulk chemicals (acrylates, malonates, 1,3-propanediol). [ABSTRACT FROM AUTHOR]

Within a newly identified set of flavin-containing monooxygenases (FMOs) from Rhodococcus jostii RHA1, we have identified three monooxygenases (FMO-E, FMO-F, and FMO-G) that are effective in catalyzing Baeyer-Villiger oxidations. These type II FMOs display relaxed coenzyme specificity by accepting both NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) and NADH (reduced form of nicotinamide adenine dinucleotide), as a coenzyme, which is a novel and attractive feature among biocatalysts capable of conducting Baeyer-Villiger oxidations. We purified FMO-E and determined that the Michaelis constants for both coenzymes were in the micromolar range, whereas the activity was highest for NADH. By using the stopped-flow technique, formation of a peroxyflavin-enzyme intermediate was observed, which indicated that type II FMOs follow a catalytic mechanism similar to that of other class B flavoprotein monooxygenases. A set of cyclobutanones and cyclohexanones were used to probe the regio- and enantioselectivity of all three recombinant monooxygenases. The biocatalysts readily accepted small cyclic ketones, which enabled the conversion of previously poorly accepted substrates by other monooxygenases (especially norcamphor), and exhibited excellent and unique regio- and enantioselectivities. Sequence analysis revealed that type II FMOs that act as Baeyer-Villiger monooxygenases contain a unique N-terminal domain. Sequence conservation in this protein domain can be used to identify new NADH-dependent Baeyer-Villiger monooxygenases, which would facilitate future biocatalyst discovery efforts. [ABSTRACT FROM AUTHOR]

This study investigates the substrate profile of cycloalkanone monooxygenase and 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-coenzyme A monooxygenase, two recently discovered enzymes of the Baeyer–Villiger monooxygenase family, used as whole-cell biocatalysts. Biooxidations of a diverse set of ketones were performed on analytical scale: desymmetrization of substituted prochiral cyclobutanones and cyclohexanones, regiodivergent oxidation of terpenones and bicyclic ketones, as well as kinetic resolution of racemic cycloketones. We demonstrated the applicability of the title enzymes in the enantioselective synthesis of (R)-(−)-Taniguchi lactone, a building block for the preparation of various natural product analogs such as ent-quinine. Graphical abstract

Smart catalysis cuts it short: Natural (S,S)‐Aerangis lactone and its epimer are synthesized with excellent optical purity by using in‐line hyphenation of continuous flow reactors and batch biotransformations. Optimization of the reaction steps and engineering of the reactor interfaces leads to a simple and efficient setup, which demonstrates how multistep syntheses can be streamlined into a single‐operation protocol. [ABSTRACT FROM AUTHOR]

Within this work a generic tool for chiral catalyst evaluation is established based on the application-oriented properties activity and selectivity; the concept aims at quantitatively comparing catalyst performance in general on a multitude of substrates. It is designed and intended to serve as decision guidance for challenges in catalysis and comprehensible information extraction from already recorded but unrefined data sets. The underlying algorithm assigns function points to catalytic entities via a statistically solid model possessing high flexibility and generates a relative ranking. This is coupled to an automated iterative refinement process towards maximum information content of results employing Shannon entropy optimization. Consequently, the developed work-flow facilitates high distinguishability between catalysts even in low-scattering data sets. The numerical ranking is complemented by a clearly arranged graphic representation permitting facile and reliable visual interpretation of generality or niche capabilities of catalysts. Usefulness of the title concept is demonstrated by the performance evaluation of cyclododecanone monooxygenase, a highly versatile Baeyer-Villiger enzyme. To retain broad applicability, an open-source MATLAB® script is provided in electronic form. [ABSTRACT FROM AUTHOR]

The article presents an overview of the re-examination process within the U.S. Patent and Trademark Office (USPTO) in the U.S. It says that re-examination proceedings within USPTO are complex regulatory procedures. It observes that in certain circumstances, re-examination proceedings could save a generic manufacturer both time and money. The article further discusses how the re-examination process might be used by generic pharmaceutical companies.

The article presents an overview of recent cases involving preliminary injunctions in pharmaceutical cases in the U.S. The author said that the U.S. district courts have the power to grant preliminary and permanent injunctions. A preliminary injunction is regarded a drastic and extraordinary remedy that is not to be routinely granted. The pharmaceutical cases where a preliminary injunction was sought include Sanofi-Synthelabo versus Apotex Inc. and Abbott Laboratories versus Apotex Inc.

Rücktitelbild: Analysis of Powders Containing Illicit Drugs Using Magnetic Levitation (Angew. Wie J. S. Bozenko, G. M. Whitesides et al. in ihrem Forschungsartikel auf S. 884 zeigen, trennt das Verfahren die Verbindungen basierend auf ihren unterschiedlichen Dichten in dem linearen Dichtegradienten, der in der Lösung gebildet wird. Die schwebenden Verbindungen (siehe Bild, aufgenommen mit gekreuzten Polarisatoren) sind gängige polare Verfälschungs- und Verdünnungsmittel, die zum Verschneiden illegaler Drogen verwendet werden. [Extracted from the article]

Many successful stories in enzyme engineering are based on the creation of randomized diversity in large mutant libraries, containing millions to billions of enzyme variants. Methods that enabled their evaluation with high throughput are dominated by spectroscopic techniques due to their high speed and sensitivity. A large proportion of studies relies on fluorogenic substrates that mimic the chemical properties of the target or coupled enzymatic assays with an optical read-out that assesses the desired catalytic efficiency indirectly. The most reliable hits, however, are achieved by screening for conversions of the starting material to the desired product. For this purpose, functional group assays offer a general approach to achieve a fast, optical read-out. They use the chemoselectivity, differences in electronic and steric properties of various functional groups, to reduce the number of false-positive results and the analytical noise stemming from enzymatic background activities. This review summarizes the developments and use of functional group probes for chemoselective derivatizations, with a clear focus on screening for enzymatic activity in protein engineering.

Magneto-Archimedes levitation (MagLev) enables the separation of powdered mixtures of illicit drugs (cocaine, methamphetamine, heroin, fentanyl, and its analogues), adulterants, and diluents based on density, and allows the presumptive identification of individual components. Small samples (mass <50 mg), with low concentrations of illicit drugs, present a particular challenge to analysis for forensic chemists. The MagLev device, a cuvette containing a solution of paramagnetic gadolinium(III) chelate in a non-polar solvent, placed between two like-poles-facing NdFeB magnets, allowed separation of seven relevant compounds simultaneously. In particular, initial separation with MagLev, followed by characterization by FTIR-ATR, enabled identification of fentanyl in a sample of fentanyl-laced heroin (1.3 wt % fentanyl, 2.6 wt % heroin, and 96.1 wt % lactose). MagLev allows identification of unknown powders in mixtures and enables confirmatory identification based on structure-specific techniques., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two biological activities of butyrate in the colon (suppression of proliferation of colonic epithelial stem cells and inflammation) correlate with inhibition of the activity of histone deacetylases. Cellular and biochemical studies of molecules similar in structure to butyrate, but different in molecular details (functional groups, chain-length, deuteration, oxidation level, fluorination, or degree of unsaturation), demonstrated that these activities were sensitive to molecular structure, and were compatible with the hypothesis that butyrate acts by binding to the Zn 2+ in the catalytic site of histone deacetylases. Structure-activity relationships drawn from a set of 36 compounds offer a starting point for the design of new compounds targeting the inhibition of histone deacetylases. The observation that butyrate was more potent than other short-chain fatty acids is compatible with the hypothesis that crypts evolved (at least in part), to separate stem cells at the base of crypts from butyrate produced by commensal bacteria.