Peroxygenase-Catalyzed Allylic Oxidation Unlocks Telescoped Synthesis of (1S,3R)-3-Hydroxycyclohexanecarbonitrile.

The unmatched chemo-, regio-, and stereoselectivity of enzymes renders them powerful catalysts in the synthesis of chiral active pharmaceutical ingredients (APIs). Inspired by the discovery route toward the LPA1-antagonist BMS-986278, access to the API building block (1S,3R)-3-hydroxycyclohexanecarbonitrile was envisaged using an ene reductase (ER) and alcohol dehydrogenase (ADH) to set both stereocenters. Starting from the commercially available cyclohexene-1-nitrile, a C-H oxyfunctionalization step was required to introduce the ketone functional group, yet several chemical allylic oxidation strategies proved unsuccessful. Enzymatic strategies for allylic oxidation are underdeveloped, with few examples on selected substrates with cytochrome P450s and unspecific peroxygenases (UPOs). In this case, UPOs were found to catalyze the desired allylic oxidation with high chemo- and regioselectivity, at substrate loadings of up to 200 mM, without the addition of organic cosolvents, thus enabling the subsequent ER and ADH steps in a three-step one-pot cascade. UPOs even displayed unreported enantioselective oxyfunctionalization and overoxidation of the substituted cyclohexene. After screening of enzyme panels, the final product was obtained at titers of 85% with 97% ee and 99% de, with a substrate loading of 50 mM, the ER being the limiting step. This synthetic approach provides the first example of a three-step, one-pot UPO-ER-ADH cascade and highlights the potential for UPOs to catalyze diverse enantioselective allylic hydroxylations and oxidations that are otherwise difficult to achieve.

Enantio-Complementary Synthesis of 2-Substituted Pyrrolidines and Piperidines via Transaminase-Triggered Cyclizations.

Chiral N-heterocycles are a common motif in many active pharmaceutical ingredients; however, their synthesis often relies on the use of heavy metals. In recent years, several biocatalytic approaches have emerged to reach enantiopurity. Here, we describe the asymmetric synthesis of 2-substituted pyrrolidines and piperidines, starting from commercially available ω-chloroketones by using transaminases, which has not yet been comprehensively studied. Analytical yields of up to 90% and enantiomeric excesses of up to >99.5% for each enantiomer were achieved, which has not previously been shown for bulky substituents. This biocatalytic approach was applied to synthesize (R)-2-(p-chlorophenyl)pyrrolidine on a 300 mg scale, affording 84% isolated yield, with >99.5% ee.

Influence of Multimodal Treatment on Rest/Activity and Autonomic Regulation in Breast Cancer Patients with Cancer-Related Fatigue: Results of a Tri-Centre Trial with a Comprehensive Cohort Design.

INTRODUCTION: Breast cancer patients with cancer-related fatigue (BC-CRF) often have lower physical activity. To investigate how this could be improved, we evaluated a multimodal treatment (MT) and a combination of MT with aerobic training (CT) and compared these with aerobic training (AT) regarding rest/activity rhythm and state autonomic regulation (State aR). METHODS: In this pragmatic comprehensive cohort design study, the explorative analysis focused on actigraphy and State aR including the rest/activity regulation subscale (State aR-R/A) which were assessed at baseline (T0), after 10 weeks of intervention (T1), and State aR additionally 6 months later (T2). STATISTICS: General linear modelling including propensity scores. RESULTS: 65 BC-CRF were randomized, and 61 were allocated by preference to the treatment arms. 105 patients started the intervention. At T1, State aR-R/A improved the most in MT (+3.49, CI [2.42; 4.55]) compared to AT (+1.59, CI [0.13; 3.06]) and CT (+1.68, CI [0.83; 2.52]), showing superiority of MT to AT (p = 0.048). At T2 MT was sustainably superior to AT regarding State aR-R/A (+3.61, CI [2.38; 4.83] p < 0.01) and State aR also showed superiority of MT to AT (p = 0.006). AT T1 24-h activity was higher in MT compared to AT (p = 0.029). CONCLUSIONS: MT was superior to AT regarding State aR total score after 6 months, State aR-R/A after 10 weeks, and after 6 months. Actigraphically measured total activity also improved after 10 weeks.

Directed evolution of phosphite dehydrogenase to cycle noncanonical redox cofactors via universal growth selection platform.

Noncanonical redox cofactors are attractive low-cost alternatives to nicotinamide adenine dinucleotide (phosphate) (NAD(P)+) in biotransformation. However, engineering enzymes to utilize them is challenging. Here, we present a high-throughput directed evolution platform which couples cell growth to the in vivo cycling of a noncanonical cofactor, nicotinamide mononucleotide (NMN+). We achieve this by engineering the life-essential glutathione reductase in Escherichia coli to exclusively rely on the reduced NMN+ (NMNH). Using this system, we develop a phosphite dehydrogenase (PTDH) to cycle NMN+ with ~147-fold improved catalytic efficiency, which translates to an industrially viable total turnover number of ~45,000 in cell-free biotransformation without requiring high cofactor concentrations. Moreover, the PTDH variants also exhibit improved activity with another structurally deviant noncanonical cofactor, 1-benzylnicotinamide (BNA+), showcasing their broad applications. Structural modeling prediction reveals a general design principle where the mutations and the smaller, noncanonical cofactors together mimic the steric interactions of the larger, natural cofactors NAD(P)+.

Biocatalytic Production of a Nylon†6 Precursor from Caprolactone in Continuous Flow.

6-Aminocaproic acid (6ACA) is a key building block and an attractive precursor of caprolactam, which is used to synthesize nylon 6, one of the most common polymers manufactured nowadays. (Bio)-production of platform chemicals from renewable feedstocks is instrumental to tackle climate change and decrease fossil fuel dependence. Here, the cell-free biosynthesis of 6ACA from 6-hydroxycaproic acid was achieved using a co-immobilized multienzyme system based on horse liver alcohol dehydrogenase, Halomonas elongata transaminase, and Lactobacillus pentosus NADH oxidase for in-situ cofactor recycling, with >90 % molar conversion (m.c.) The integration of a step to synthesize hydroxy-acid from lactone by immobilized Candida antarctica lipase B resulted in >80 % m.c. of ϵ-caprolactone to 6ACA, >20 % of δ-valerolactone to 5-aminovaleric acid, and 30 % of γ-butyrolactone to γ-aminobutyric acid in one-pot batch reactions. Two serial packed-bed reactors were set up using these biocatalysts and applied to the continuous-flow synthesis of 6ACA from ϵ-caprolactone, achieving a space-time yield of up to 3.31 g6ACA h-1 L-1 with a segmented liquid/air flow for constant oxygen supply.

Influence of Reaction Conditions on Enzymatic Enantiopreference: the Curious Case of HEwT in the Synthesis of THF-Amine.

Enzymatic enantiopreference is one of the key advantages of biocatalysis. While exploring the synthesis of small cyclic (chiral amines) such as 3-aminotetrahydrofuran (THF-amine), using the (S)-selective transaminase from Halomonas elongata (HEwT), inversion of the enantiopreference was observed at increasing substrate loadings. In addition, the enantiopreference could be altered by variation of the ionic strength, or of the co-solvent content in the reaction mixture. For example, using otherwise identical reaction conditions, the presence of 2 M sodium chloride gave (R)-THF-amine (14 % ee), while the addition of 2.2 M isopropyl alcohol gave the (S)-enantiomer in 30 % ee. While the underlying cause is not currently understood, it appears likely that subtle changes in the structure of the enzyme cause the shift in enantiopreference and are worth exploring further.

GPhos Ligand Enables Production of Chiral N-Arylamines in a Telescoped Transaminase-Buchwald-Hartwig Amination Cascade in the Presence of Excess Amine Donor.

The combination of biocatalysis and chemocatalysis can be more powerful than either technique alone. However, combining the two is challenging due to typically very different reaction conditions. Herein, chiral N-aryl amines, key features of many active pharmaceutical ingredients, are accessed in excellent enantioselectivity (typically>99.5 % ee) by combining transaminases with the Buchwald-Hartwig amination. By employing a bi-phasic buffer-toluene system as well as the ligand GPhos, the telescoped cascade proceeded with up to 89 % overall conversion in the presence of excess alanine. No coupling to alanine was observed.

Producing natural vanilla extract from green vanilla beans using a ß-glucosidase from Alicyclobacillus acidiphilus.

Current methods for the production of natural vanilla extract are long and tedious, and the efficiency of the vanillin extraction is usually conditioned by different factors during the traditional curing process (temperatures and weather conditions). As an important fraction of vanillin is present in the form of glucovanillin in green beans, endogenous ß-glucosidases contribute to its hydrolysis; however, these enzymes lose efficiency during the curing process. The use of extremophilic organisms as a source of an appropriate exogenous enzyme can offer a valid alternative when producing natural vanillin. Here, a ß-glucosidase from the thermo-acidophilic organism Alicyclobacillus acidiphilus (AacGH1) was cloned, expressed in E. coli BL21, and fully characterized in respect to both function and crystal structure. Notably, AacGH1 was stable at a temperature up to 50 °C and exhibited good tolerance to glucose, fructose and organic solvents, in particular it maintained full activity in the presence of up to 20 % (v/v) ethanol. The enzyme was then successfully applied to an ethanol-water (20 % (v/v)) extract of green vanilla beans and the complete hydrolysis of glucovanillin (1.7 mM) to vanillin, and other flavour compounds commonly found in vanilla, was achieved using 0.5 mg/mL of enzyme in just 15 min at 30 °C.

Release of Soybean Isoflavones by Using a ß-Glucosidase from Alicyclobacillus herbarius.

ß-Glucosidases are used in the food industry to hydrolyse glycosidic bonds in complex sugars, with enzymes sourced from extremophiles better able to tolerate the process conditions. In this work, a novel ß-glycosidase from the acidophilic organism Alicyclobacillus herbarius was cloned and heterologously expressed in Escherichia coli BL21(DE3). AheGH1 was stable over a broad range of pH values (5-11) and temperatures (4-55 °C). The enzyme exhibited excellent tolerance to fructose and good tolerance to glucose, retaining 65 % activity in the presence of 10 % (w/v) glucose. It also tolerated organic solvents, some of which appeared to have a stimulating effect, in particular ethanol with a 1.7-fold increase in activity at 10 % (v/v). The enzyme was then applied for the cleavage of isoflavone from isoflavone glucosides in an ethanolic extract of soy flour, to produce soy isoflavones, which constitute a valuable food supplement, full conversion was achieved within 15 min at 30 °C.

Looking Back: A Short History of the Discovery of Enzymes and How They Became Powerful Chemical Tools.

Enzymatic approaches to challenges in chemical synthesis are increasingly popular and very attractive to industry given their green nature and high efficiency compared to traditional methods. In this historical review we highlight the developments across several fields that were necessary to create the modern field of biocatalysis, with enzyme engineering and directed evolution at its core. We exemplify the modular, incremental, and highly unpredictable nature of scientific discovery, driven by curiosity, and showcase the resulting examples of cutting-edge enzymatic applications in industry.

An (R)-Selective Transaminase From Thermomyces stellatus: Stabilizing the Tetrameric Form.

The identification and 3D structural characterization of a homolog of the (R)-selective transaminase (RTA) from Aspergillus terreus (AtRTA), from the thermotolerant fungus Thermomyces stellatus (TsRTA) is here reported. The thermostability of TsRTA (40% retained activity after 7 days at 40°C) was initially attributed to its tetrameric form in solution, however subsequent studies of AtRTA revealed it also exists predominantly as a tetramer yet, at 40°C, it is inactivated within 48 h. The engineering of a cysteine residue to promote disulfide bond formation across the dimer-dimer interface stabilized both enzymes, with TsRTA_G205C retaining almost full activity after incubation at 50°C for 7 days. Thus, the role of this mutation was elucidated and the importance of stabilizing the tetramer for overall stability of RTAs is highlighted. TsRTA accepts the common amine donors (R)-methylbenzylamine, isopropylamine, and d-alanine as well as aromatic and aliphatic ketones and aldehydes.

Widely applicable background depletion step enables transaminase evolution through solid-phase screening.

Directed evolution of transaminases is a widespread technique in the development of highly sought-after biocatalysts for industrial applications. This process, however, is challenged by the limited availability of effective high-throughput protocols to evaluate mutant libraries. Here we report a rapid, reliable, and widely applicable background depletion method for solid-phase screening of transaminase variants, which was successfully applied to a transaminase from Halomonas elongata (HEWT), evolved through rounds of random mutagenesis towards a series of diverse prochiral ketones. This approach enabled the identification of transaminase variants in viable cells with significantly improved activity towards para-substituted acetophenones (up to 60-fold), as well as tetrahydrothiophen-3-one and related substrates. Rationalisation of the mutants was assisted by determination of the high-resolution wild-type HEWT crystal structure presented herein.

Colchicum autumnale in Patients with Goitre with Euthyroidism or Mild Hyperthyroidism: Indications for a Therapeutic Regulative Effect-Results of an Observational Study.

Introduction. Goitre with euthyroid function or with subclinical or mild hyperthyroidism due to thyroid autonomy is common. In anthroposophic medicine various thyroid disorders are treated with Colchicum autumnale (CAU). We examined the effects of CAU in patients with goitre of both functional states. Patients and methods. In an observational study, 24 patients with goitre having suppressed thyroid stimulating hormone (TSH) levels with normal or slightly elevated free thyroxine (fT4) and free triiodothyronine (fT3) (group 1, n = 12) or normal TSH, fT3, and fT4 (group 2, n = 12) were included. After 3 months and after 6 to 12 months of CAU treatment, we investigated clinical pathology using the Hyperthyroid Symptom Scale (HSS), hormone status (TSH, fT4, and fT3), and thyroidal volume (tV). Results. After treatment with CAU, in group 1 the median HSS decreased from 4.5 (2.3-11.8) to 2 (1.3-3) (p < 0.01) and fT3 decreased from 3.85 (3.5-4.78) to 3.45 (3.3-3.78) pg/mL (p < 0.05). In group 2 tV (13.9% (18.5%-6.1%)) and TSH (p < 0.01) were reduced. Linear regression for TSH and fT3 in both groups indicated a regulative therapeutic effect of CAU. Conclusions. CAU positively changed the clinical pathology of subclinical hyperthyroidism and thyroidal volume in patients with euthyroid goitre by normalization of the regulation of thyroidal hormones.

Thyrotropin receptor autoantibodies are independent risk factors for Graves' ophthalmopathy and help to predict severity and outcome of the disease.

OBJECTIVE: The objective of this study was to examine whether TSH-receptor antibody [TSH binding inhibitory antibodies (TBII)] levels are associated with the severity of Graves' ophthalmopathy (GO) over the entire course of the disease. METHODS AND PATIENTS: A total of 159 patients with GO were followed for 12-24 months. One year after the first symptoms of GO, all patients were classified into mild or severe GO according to their clinical manifestations. TBII were measured every 3 months after onset of GO. Receiver operating characteristic plot analysis was performed to assess the power to discriminate both patient groups by TBII (specificity >90%). RESULTS: TBII levels and prevalence at each time point during follow-up were significantly higher in patients with a severe course of GO compared with patients with a mild course of GO. Prognostic statements on the course of the disease were possible for about half of the GO patients at all time points (except the first). If at first presentation and at consecutive time points TBII levels were less than 5.7, 2.6, 1.5, 1.5, 1.5, and 1.5 IU/liter, the patients had a 2.3- to 15.6-fold higher chance of a mild course. If 5-8 months after GO onset and at consecutive time points TBII levels were above 8.8, 5.1, 4.8, 2.8, and 2.8 IU/liter, the patients had a 8.7- to 31.1-fold higher risk of a severe course. This relationship of TBII to the severity was independent from age and smoking. CONCLUSION: Follow-up measurements of TBII allow, in half of the patients, assessment of the prognosis of GO and, therefore, could be of additional help for the disease management.

[Reduction of endogenous regulation in internal medicine patients]. / Verlust von endogener Regulation bei internistischen Patienten.

BACKGROUND: General health-related questionnaires on quality of life do not satisfactorily distinguish between healthy and sick people. One of the reasons cited for this lack is too much mental influence. This is why we developed a questionnaire on endogenous regulation (eR) that reflects the regulatory state of various vegetative functions. OBJECTIVE: The current study examines whether the short version eR questionnaire is able to distinguish between healthy people and internal medicine patients. PATIENTS AND METHODS: 408 participants were included in the study (284 females, 124 males). Among these were patients with colorectal cancer (n = 49), breast cancer (n = 95), diabetes mellitus (type 1: n = 20, type 2: n = 40), coronary disease (n = 39), rheumatoid illnesses (n = 28) and multimorbid patients (n = 22) as well as a healthy control group (n = 115). In addition to the eR questionnaire the study also used the Hospital Anxiety and Depression Scale (HADS), the short questionnaire on self-regulation and questions on the vegetative status. RESULTS: The healthy control group showed the highest eR, with an estimated average of M = 29.8. Patients with breast cancer, diabetes mellitus type 2, coronary disease and rheumatoid illnesses reveal a significantly lowered eR. Multimorbid patients show the lowest eR. Patients with cancer of the colon and diabetes type 1 were measured at M = 27.9 and M = 27.3 respectively and showed no significantly lowered estimated average compared to the control group. A high eR significantly correlates (p < 0.002) with the following parameters: low levels of anxiety (r = 49) and depression (r = 0.36), high self-regulation (r = 0.34), morning type (r = 0.40), less congestive perspiration (r = 0.38), less shivering (r = 0.23), dysmenorrhoea (r = 0.38) and allergies (r = 0.17). CONCLUSION: Healthy people show the highest, multimorbid patients the lowest eR. Consistent relations to health, illness, heat regulation and personality presence have been shown. Further studies to clarify clinical relevance are necessary.

[Chronic distress syndrome in patients with Graves' disease]. / Chronisches Distress-Syndrom bei Patientinnen mit behandelter Autoimmunhyperthyreose.

PURPOSE: Cross-sectional study to evaluate the psychological distress of patients with Graves' disease 5 years after diagnosis. PATIENTS AND METHODS: 45 female patients being treated for Graves' disease in a specialized endocrinological practice in Wuppertal, Germany, were asked to fill in the Symptom Checklist-90-R (SCL-90-R) and the Hospital Anxiety and Depression Scale (HADS). All patients were in a euthyroid state for at least 6 months. RESULTS: Patients were found to have significantly elevated mean values in the SCL-90-R compared with normal values for healthy test candidates. According to the Global Severity Index (GSI) more than one third (35.6%) of patients were suffering from psychological distress. These patients also showed elevated scores in the anxiety subscale of HADS. Almost all patients (95.6%) had elevated scores in the depression subscale of HADS. Patients with high levels of psychological distress (GSI > 60) were more likely to suffer a relapse than those with normal levels (p < 0.05). Patients in latent hyperthyroid state did not show higher levels of psychological distress than those with normal thyrotropin (TSH). CONCLUSION: Many patients with a history of Graves' disease suffer from chronic psychological distress which cannot be explained by the metabolic state of the thyroid gland. Whether this finding results from damage to the CNS or reflects a generally increased stress vulnerability is unclear. Psychological treatment appears to be indicated in many cases of Graves' disease.

Effects of an anthroposophical remedy on cardiorespiratory regulation.

CONTEXT: The human organism has the inherent ability to regulate and coordinate physiological functions to establish well-being. If this ability is disturbed, eg, in cases of orthostatic syndrome with purely functional disorders, an herbal remedy based on anthroposophical medicine may be able to regulate such rhythmic disturbances. OBJECTIVE: To determine the effect of the anthroposophical herbal remedy on stimulating the ability to regulate and coordinate physiological functions in healthy subjects. DESIGN: Double-blind, placebo-controlled, randomized trial PARTICIPANTS: Ninety-nine healthy subjects; 49 received the remedy, 50 received the placebo. INTERVENTION: Oral administration of the remedy for 4 weeks, 20 drops 4 times daily. MAIN OUTCOME MEASURES: Cardiorespiratory interaction was analyzed by 2 measures: the heart-respiratory ratio and the phase-coordination ratio of heartbeat and respiration. They were calculated from heart rate and respiratory rate, which were derived from 24-hour electrocardiogram recordings before and after the administration of the remedy. Improved normalization of these measures during nighttime sleep after administration of the remedy indicates a stimulation of regulation. RESULTS: Oral administration of the remedy resulted in an improved normalization of heart-respiratory ratio, phase-coordination ratio and heart rate during nighttime sleep. These results were not observed in the placebo group. CONCLUSIONS: The remedy stimulates the regulation of cardiorespiratory interaction during nighttime sleep. Furthermore, improved normalization indicates a general improvement of the regulatory processes of functional rhythms.