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Biocatalysis harnesses enzymes to make valuable products. This green technology is used in countless applications from bench scale to industrial production and allows practitioners to access complex organic molecules, often with fewer synthetic steps and reduced waste. The last decade has seen an explosion in the development of experimental and computational tools to tailor enzymatic properties, equipping enzyme engineers with the ability to create biocatalysts that perform reactions not present in nature. By using (chemo)-enzymatic synthesis routes or orchestrating intricate enzyme cascades, scientists can synthesize elaborate targets ranging from DNA and complex pharmaceuticals to starch made in vitro from CO2-derived methanol. In addition, new chemistries have emerged through the combination of biocatalysis with transition metal catalysis, photocatalysis, and electrocatalysis. This review highlights recent key developments, identifies current limitations, and provides a future prospect for this rapidly developing technology.

Copyright © 2016 John Wiley & Sons, Ltd. Sport supplements containing steroids never approved for therapeutic use have the potential for abuse by athletes. Most are marketed online and may contain undisclosed steroids yet are readily available despite lacking toxicological or pharmacological evaluation. In this study, 18 supplements purchased online underwent organic solvent extraction to isolate any steroids they contained. From the 18 supplements, 19 steroids were identified and for each, its intrinsic androgenic potency was determined by a yeast cell (Saccharomyces cerevisiae) androgen bioassay and its potential androgenic potency was determined by a liver (HuH7) cell androgen bioassay. The yeast bioassay showed that of the 19 steroids tested, 6 demonstrated strong intrinsic bioactivity, with 4 metabolically activated to even stronger androgens. Moreover, 4 steroids with moderate and 1 with intrinsically weak androgenic bioactivity were activated to more potent androgens. Finally, 8 steroids were metabolically inactivated or deactivated into weaker androgens. Our results show that Internet-sourced sport supplements may contain intrinsically strong androgens, or precursors that can be metabolized to them. These potentially potent pharmacologically active steroids are being used without regulatory control or consumer awareness of their potential adverse effects. Copyright © 2016 John Wiley & Sons, Ltd.

Context: Management of male infertility and/or androgen deficiency requires accurate hormonal measurements with valid reference intervals. Objective(s): The objective of this study was to develop a valid reference panel of blood samples from healthy eugonadal young men with verified normal reproductive function and to use this panel to evaluate the performance of seven fully automated, commercial multiplex immunoassay platforms used to measure serum total testosterone (T), LH, and FSH. Design(s): This was an observational study of consistency among seven different automated immunoassays for each of total T, LH, and FSH. Each method was implemented in two laboratories, with each repeating the analysis of the full reference panel samples twice. Serum T concentrations were also measured by gas chromatography/mass spectrometry (GC/MS), and serum inhibin B levels were determined by an ELISA. Setting(s): The study was performed at commercial, high-volume, clinical pathology laboratories. Participant(s): From 147 men screened, sera from 124 healthy, reproductively normal men (age, 21-35 yr) with normal sperm output were used as a reference panel. All laboratories selected for elite performance in the national immunoassay quality assurance program agreed to participate. Main Outcome Measure(s): For each of the 868 assays, descriptive statistics were calculated in the natural and log-transformed scales and were analyzed by nested, repeated measures ANOVA after log transformation. Reference intervals, defined as 95% confidence limits, were calculated using arithmetic (natural scale), geometric (log scale) and nonparametric methods. Result(s): Descriptive statistics and reference intervals for serum T, LH, and FSH differed widely and significantly between methods, but variation between laboratories for the same assay was negligible. All T methods showed significant differences in regression slope and intercept in deviance plots as well as in estimated reference ranges compared

BACKGROUND: The utility of insulinlike growth factor (IGF) axis and collagen markers for a growth hormone (GH) doping test in sport depends on their stability and reproducibility. We sought to determine short-term within-subject variability of these markers in a large cohort of healthy individuals. METHODS: We measured IGF-I, IGF binding protein 3 (IGFBP-3), acid labile subunit (ALS), and the collagen markers N-terminal propeptide of type I procollagen (PINP), C-terminal telopeptide of type I collagen (ICTP), and N-terminal propeptide of type III procollagen (PIIINP) in serum samples obtained on multiple occasions (median 3 per participant) over a 2- to 3-week period from 1103 elite athletes (699 men, 404 women) ages 22.2 (5.2) years [mean (SD)]. We estimated between-subject and within-subject variances by mixed-effects ANOVA. RESULTS: Within-subject variance accounted for 32% to 36% and 4% to 13% of the total variance in IGF markers and collagen markers, respectively. The within-subject CV ranged from 11% to 21% for the IGF axis markers and from 13% to 15% for the collagen markers. The index of individuality for the IGF axis markers was 0.66-0.76, and for the collagen markers, 0.26-0.45. For each marker, individuals with initial extreme measured values tended to regress toward the population mean in subsequent repeated measurements. We developed a Bayesian model to estimate the long-term probable value for each marker. CONCLUSIONS: These results indicate that in healthy individuals the within-subject variability was greater for IGF-I than for the collagen markers, and that where a single measurement is available, it is possible to estimate the long-term probable value of each of the markers by applying the Bayesian approach. Such an application can increase the reliability and decrease the cost of detecting GH doping. © 2008 American Association for Clinical Chemistry.

The recent identification of tetrahydrogestrinone (THG), a non-marketed designer androgen used for sports doping but previously undetectable by established mass spectrometry-based urine drug screens, and its production by a facile chemical modification of gestrinone has raised concerns about the risks of developing designer androgens from numerous marketed progestins. We therefore have used yeast-based in vitro androgen and progesterone bioassays to conduct a structure-activity study assessing the intrinsic androgenic potential of commercially available progestins and their derivatives, to identify those compounds or structures with the highest risk of forming a basis for such misapplication. Progestins had a wide range of androgenic bioactivity that was not reliably predicted for individual steroids by their progestin bioactivity. 17alpha-Hydroxyprogesterone and 19-norprogesterone derivatives with their bulky 17beta-substituents were strong progestins but generally weak androgens. 17alpha-Ethynylated derivatives of testosterone, 19-nortestosterone and 18-methyl-19-nortestosterone such as gestrinone, ethisterone, norethisterone and norgestrel had the most significant intrinsic androgenicity of all the commercially marketed progestins. Facile chemical modification of the 17alpha-ethynyl group of each of these progestins produces 17alpha-methyl, ethyl and allyl derivatives, including THG and norbolethone, which further enhanced androgenic bioactivity. Thus by using the rapid and sensitive yeast bioassay we have screened a comprehensive set of progestins and associated structures and identified the ethynylated testosterone, 19-nortestosterone and 18-methyl-19-nortestosterone derivatives as possessing the highest risk for abuse and potential for conversion to still more potent androgens. By contrast, modern progestins such as progesterone, 17alpha-hydroxyprogesterone and 19-norprogesterone derivatives had minimal androgenic bioactivity and pose low risk.

(Chemical Equation Presented) Changing substrates: A mutation that forms a cis-proline-peptide bond in a loop structure close to the active site of an aryl esterase from Pseudomonas fluorescens converts the enzyme into a perhydrolase (see picture). The switch in activity is explained by a new hydrogen bond formed between a backbone carbonyl oxygen atom and the peroxy deacylation intermediate.

Rational design of enzymes with improved properties, such as enantioselectivity, usually focuses mutations within the substrate binding site. On the other hand, directed evolution of enzymes usually targets the entire protein and discovers beneficial mutations far from the substrate binding site. In this paper, we propose an explanation for this discrepancy and show that a combined approach-random mutagenesis within the substrate binding site-is better. To increase the enantioselectivity (E) of a Pseudomonas fluorescens esterase (PFE) toward methyl 3-bromo-2-methylpropionate, we focused mutagenesis into the substrate binding site at Trp28, Val121, Phe198, and Val225. Five of the catalytically active mutants (13%) showed better enantioselectivity than wild-type PFE. The increases in enantioselectivity were higher (up to 5-fold, reaching E = 61) than with mutants identified by random mutagenesis of the entire enzyme., QC 20100525

QCR 20190204

The structure of PFE, an aryl esterase from Pseudomonas fluorescens, has been solved to a resolution of 1.8 Å by X-ray diffraction and shows a characteristic α/β-hydrolase fold. In addition to catalyzing the hydrolysis of esters in vitro, PFE also shows low bromoperoxidase activity. PFE shows highest structural similarity, including the active-site environment, to a family of non-heme bacterial haloperoxidases, with an r.m.s. deviation in 271 Cα atoms between PFE and its five closest structural neighbors averaging 0.8 Å. PFE has far less similarity (r.m.s. deviation in 218 Cα atoms of 5.0 Å) to P. fluorescens carboxyl esterase. PFE favors activated esters with small acyl groups, such as phenyl acetate. The X-ray structure of PFE reveals a significantly occluded active site. In addition, several residues, including Trp28 and Met95, limit the size of the acyl-binding pocket, explaining its preference for small acyl groups., QC 20141215

A simple means of detecting the abuse of steroids that also occur naturally is a problem facing doping control laboratories. Specific markers are required to allow the detection of the administration of these steroids. These markers are commonly measured using a set of data obtained from the screening of samples by gas chromatography-mass spectrometry (GC-MS). Doping control laboratories further need to confirm identified abuse using techniques such as gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). An interesting urinary species was found while following the pharmacokinetics and changes to the steroid profile from single and multiple oral doses of the International Olympic Committee/World Anti Doping Agency (IOC/WADA) prohibited substance, dehydroepiandrosterone (DHEA). The urine samples collected from the administration studies were subject to GC-MS and GC-C-IRMS steroid analysis following cleanup by solid phase extraction techniques. A useful urinary product of DHEA administration was detected in the urine samples from each of the administration studies and was identified by GC-MS experiments to be 3alpha,5-cyclo-5alpha-androstan-6beta-ol-17-one (3alpha,5-cyclo). This compound occurs naturally but the concentrations of 3alpha,5-cyclo were elevated following both the single DHEA administration (up to 385 ng/mL) and multiple DHEA administrations (up to 1240 ng/mL), in relation to those observed prior to these administrations (70 and 80 ng/mL, respectively). A reference distribution of urine samples collected from elite athletes (n = 632) enabled the natural concentration range of 3alpha,5-cyclo to be established (0-280 ng/mL), with a mean concentration of 22 ng/mL. Based on this an upper 3alpha,5-cyclo concentration limit of 140 ng/mL is proposed as a GC-MS screening marker of DHEA abuse in athletes. GC-C-IRMS analysis revealed significant 13C depletion of 3alpha,5-cyclo following DHEA administration. In the single administration study, t

L- Ascorbic acid ( vitamin C) is a useful natural antioxidant, but is highly polar and does not dissolve in fats and oils. One solution is the synthesis of 6- O- L- ascorbyl fatty acid esters, which are surface- active and protect fats and oils from oxidation. Previous syntheses of 6- O- L- ascorbyl fatty acid esters by Candida antarctica lipase B ( CAL- B)- catalysed esterification were inefficient due to either the poor solubility of L- ascorbic acid in nonpolar organic solvents or poor lipase activity in polar organic solvents. We report that replacing organic solvents with ionic liquids such as 1- alkyl- 3- methylimidazolium tetrafluoroborates makes this synthesis more efficient and greener for three reasons. First, like polar organic solvents, ionic liquids dissolve polar substrates such as ascorbic acid ( e. g., similar to 130 mg mL(-1) in sBMIM . BF4 at 60degreesC), but unlike polar organic solvents, ionic liquids do not inactivate CAL- B. For this reason, using an ionic liquid as the solvent gave a faster reaction and a higher yield of product. Second, it eliminates toxic organic solvents that easily evaporate. Third, since ionic liquids are not volatile, we could use vacuum to drive the equilibrium toward product formation. This ability eliminated the need to use an excess of acyl donor or an activated acyl donor. One problem we encountered was product inhibition due to its precipitation on the immobilized lipase particles. To avoid this inhibition, we added a hydrophobic phase such as hexane or polypropylene beads. A CAL- B- catalysed direct esterification of stoichiometric amounts of ascorbic acid and oleic acid gave a high conversion ( 83%). The product 6- O- L- ascorbyl oleate was isolated as a mixture with oleic acid using only water and ethanol or methanol in 61% yield., QC 20100525