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The enzyme system mimicking Implication (IMPLY) and Inhibition (INHIB) Boolean logic gates has been designed. The same enzyme system was used to operate as the IMPLY or INHIB gate simply by reformulating the input signals. The optical analysis of the logic operation confirmed the output generation as expected for the studied logic gates. The conceptual approach to the IMPLY and INHIB logic gates allows their construction with many other enzymes operating in a similar way.

Different analytical (enzyme system and near-infrared spectroscopy (NIRS)) and statistical (single and multiple regressions) approaches were used to predict in vivo standardized pre-caecal digestibility (PCD) of crude protein (CP) and amino acids (AA) in cereal grains for growing pigs as well as in vitro nitrogen (N) solubility. Furthermore, different chemical and physical characteristics were categorized (e.g. crude nutrients, AA, minerals, fibre components or combinations of these) and used for generating prediction equations. There were strong linear relationships (p

Copper has been used from ancient time in various applications. Scientists have exploited its means of exposure and consequences to living organisms. The peculiar property of nanomaterials that is a high surface to volume ratio has increased the range of application in products. Copper oxide nanoparticles (CuO NPs) are widely used in industrial applications such as semiconductor devices, gas sensor, batteries, solar energy converter, microelectronics, heat transfer fluids and consumer products. In contrast, acute toxicity of CuO NPs has also been reported. Subsequently, human and environmental health may be at a high risk. Their frequent use can also contaminate ecosystems. Therefore, the toxicity of CuO NPs needs to be thoroughly understood. In this review, we have tried to discuss the recent facts and mechanism that have been explored for CuO NPs-induced toxicity at a cellular, in vivo and ecotoxicological level. Accordingly, the main cause for induction of toxicity by CuO NPs is the generation of reactive oxygen species (ROS) followed by the mitochondrial destruction that leads to apoptosis via the intrinsic pathway or under the condition such as hypoxia cell on exposure to CuO NPs may commit to necrosis. Moreover, CuO NPs also result in activation of MAPK pathways, ERKs and JNK/SAPK thus play an important role in the activation of AP-1. Furthermore, CuO NPs also leads to up-regulation of p53 and caspase three genes. Therefore, careful measures are required to explore omic technology to understand the molecular mechanism of the deleterious effects caused by CuO NPs. Copyright © 2016 John Wiley & Sons, Ltd.

Summary This review seeks to re-introduce cystic fibrosis (CF) clinicians to the pharmacology of drug–drug interactions among medications commonly used in CF and provide a framework for understanding these interactions among medications outside the scope of this discussion. We here focus on drugs impacted by the cytochrome P-450 (CYP450) enzyme system and on interactions involving antimicrobials, psychotropic medications, and cystic fibrosis transmembrane conductance regulator (CFTR) modulators. Particular attention is needed when prescribing rifampin, azole antifungals and the CFTR modulators, ivacaftor, and lumacaftor/ivacaftor, in combination with other medications. The complexities of these interactions provide a strong rationale for case management by pharmacists and pharmacologists as a routine part of CF care. Pediatr Pulmonol. 2016;51:S61–S70. © 2016 Wiley Periodicals, Inc.

The molybdenum and vanadium nitrogenases are two homologous enzymes with distinct structural and catalytic features. Previously, it was demonstrated that the V nitrogenase was nearly 700 times more active than its Mo counterpart in reducing CO to hydrocarbons. Herein, a similar discrepancy between the two nitrogenases in the reduction of CO2 is reported, with the V nitrogenase being capable of reducing CO2 to CO, CD4, C2D4, and C2D6, and its Mo counterpart only capable of reducing CO2 to CO. Furthermore, it is shown that the V nitrogenase may direct the formation of CD4 in part via CO2-derived CO, but that it does not catalyze the formation of C2D4 and C2D6 along this route. The exciting observation of a V nitrogenase-catalyzed CC coupling with CO2 as the origin of the building blocks adds another interesting reaction to the catalytic repertoire of this unique enzyme system. The differential activities of the V and Mo nitrogenases in CO2 reduction provide an important framework for systematic investigations of this reaction in the future.

Molecularly ordered composites of polyvinylimidazole-[Os(bipyridine)2Cl] (PVI-[Os(bpy)2Cl]) and glucose oxidase (GOD) are assembled inside a film of aligned carbon nanotubes. The structure of the prepared GOD/PVI-[Os(bpy)2Cl]/CNT composite film is entirely uniform and stable; more than 90% bioelectrocatalytic activity could be maintained even after storage for 6 d. Owing to the ideal positional relationship achieved between enzyme, mediator, and electrode, the prepared film shows a high bioelectrocatalytic activity for glucose oxidation (ca. 15 mA cm−2 at 25 °C) with an extremely high electron-transfer turnover rate (ca. 650 s−1) comparable to the value for GOD solutions, indicating almost every enzyme molecule entrapped within the ensemble (ca. 3 × 1012 enzymes in a 1 mm × 1 mm film) can work to the fullest extent. This free-standing, flexible composite film can be used by winding on a needle device; as an example, a self-powered sugar monitor is demonstrated.

Received: December 23, 2011; Revised: April 23, 2012; Published online: July 29, 2012Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201101006.Abstract: The use of ene-reductase (ERED) en-zymes for the asymmetric reduction of olefins offersa green, renewable alternative to metal-catalysedasymmetric reduction. We report herein the first ex-ample of an ERED-catalysed enantiospecific reduc-tion carried out at large scale using a carbonyl reduc-tase (CRED) enzyme in the cofactor recycle. This re-action has been paired with a hydrolase-mediated re-gioselective ester hydrolysis to generate a valuablechiral building block using a straightforward one-potprocess.Keywords: asymmetric synthesis; biocatalysis; chiral-ity; enzyme catalysis; hydrogenation; hydrolases; re-duction

Downstream processing for isomaltose by purification on BEA-zeolites was investigated. The important process steps are washing procedure, desorption, and reactivation of the adsorbent. Purity and yield were influenced by the enzyme system. Desorption kinetics was determined at 50 ° and 70 °C. Complete desorption was performed in a three stage cross-flow-sequence. The reactivation of BEA-zeolite is feasible with additional effort for Na+-cation exchange.

1 It is probable that the “original” yellow enzyme system of Warburg is responsible for a part of the Michaelis Salomon reaction. 2 There are strong arguments against the functioning of amino-acid oxidase and xanthine oxidase.

The hepoxilin pathway was discovered over two decades ago. Products in this pathway are derived through the 12S-lipoxygenase/hepoxilin synthase enzyme system and contain intrinsic biological activity. This activity relates to the reorganization of calcium and potassium ions within the cell, and in inflammation and insulin secretion. Although the natural hepoxilins are chemically unstable, chemical analogues (PBTs) have been synthesized with chemical and biological stability. The PBTs antagonize the natural hepoxilins. The PBTs showed bioavailability, excellent tolerance and stability in vivo. In proof of principle studies in vivo in animal models, the PBTs have shown actions as anti-inflammatory agents, anti-thrombotic agents, anti-cancer agents and anti-diabetic agents. These studies demonstrate the effectiveness of the base structure of the hepoxilin (and PBT) molecule and serve as an excellent framework for the design and preparation of second-generation compounds with improved pharmaceutical properties as therapeutics for the above-mentioned diseases.

The effect of corticosteroid on the rate of biotransformation of cyclophosphamide in man was studied. Two opposite effects could be demonstrated. The immediate effect consisted of an inhibition of the biotransformation probably due to the inhibition of the hepatic drug-metabolizing enzymes whereas prolonged treatment with prednisone resulted in an increased rate of biotransformation of cyclophosphamide, probably due to the induction of the same enzyme system.

A novel one-pot, two-step, two-enzyme cascade is described. Pro-chiral α-chloro ketones are stereoselectively reduced to the corresponding halohydrins as an intermediate by a biocatalytic hydrogen transfer process. The intermediate is transformed to the corresponding epoxide by a non-enantioselective halohydrin dehalogenase. Thus, by combining a Prelog- or anti-Prelog alcohol dehydrogenase with a non-selective halohydrin dehalogenase, enantiopure (R)- as well as (S)-epoxides were obtained.

Fatty acid synthase (E.C. 2.3.1.85; FASN) is a multifunctional enzyme system that catalyzes the formation of fatty acids from acetyl-CoA, malonyl-CoA, and NADPH and plays a central role in lipid biosynthesis. Two classes of FASN exist: FASN I in animals and fungi, and FASN II in plants and prokaryotes. Animal FASN I is a homodimeric protein found in the cytosol of lipogenic tissues such as the liver and brain. Many human carcinomas exhibit elevated levels of FASN I, though the benefit to cancer cells is still unclear. Inhibition of FASN I selectively effects apoptosis in cancer cells, and the role of FASN I in chemotherapy is a growing area of research with the use of natural products and small molecule inhibitors.

With the continuous increase in fossil fuels consumption and the rapid growth of atmospheric CO2 concentration, the harmonious state between human and nature faces severe challenges. Exploring green and sustainable energy resources and devising efficient methods for CO2 capture, sequestration and utilization are urgently required. Converting CO2 into fuels/chemicals/materials as an indispensable element for CO2 capture, sequestration and utilization may offer a win–win strategy to both decrease the CO2 concentration and achieve the efficient exploitation of carbon resources. Among the current major methods (including chemical, photochemical, electrochemical and enzymatic methods), the enzymatic method, which is inspired by the CO2 metabolic process in cells, offers a green and potent alternative for efficient CO2 conversion due to its superior stereo-specificity and region/chemo-selectivity. Thus, in this tutorial review, we firstly provide a brief background about enzymatic conversion for CO2 capture, sequestration and utilization. Next, we depict six major routes of the CO2 metabolic process in cells, which are taken as the inspiration source for the construction of enzymatic systems in vitro. Next, we focus on the state-of-the-art routes for the catalytic conversion of CO2 by a single enzyme system and by a multienzyme system. Some emerging approaches and materials utilized for constructing single-enzyme/multienzyme systems to enhance the catalytic activity/stability will be highlighted. Finally, a summary about the current advances and the future perspectives of the enzymatic conversion of CO2 will be presented.

A coupled enzyme system in one pot allows the preparation of the title compounds in enantiomerically pure form.

3-Acetylpyridine-adenine dinucleotide, reduced form (AcPdADH) is able to act as an alternative reductant in glutamate-synthase-catalysed glutamate synthesis. In the AcPdADH-dependent reaction, kcat and Km values for the other substrates are fourfold lower than those for the NADH-dependent reaction, and Km for AcPdADH is about 3 μM. AcPdADH acts as a competitive inhibitor with respect to NADH in NADH-dependent glutamate synthesis, with a Ki of 1 fμM. Glutamate synthase catalyses NADH-dependent reduction of AcPdAD+. This appears to proceed by a substituted-enzyme (ping-pong) mechanism, with competitive substrate inhibition by NADH at high levels. The Km value for this reaction are 1.4 μM for NADH and 14 μM for ACPdAD+ and kcat, is 51 s−; K1 for NADH is about 10 μM. The latter findings suggest that NADH is capable of reducing the enzyme molecule in the absence of other substrates and that a reduced form of the enzyme can exist in the absence of bound NADH.

Streptomyces K15 possesses a set of exocellular and cell-bound D-alanyl-D-alanine carboxypeptidases. Four of them have been isolated to the stage where each enzyme preparation contains on single penicillin-binding protein. The exocellular 54000-Mr enzyme is extremely sensitive to benzylpenicillin and performs low transpeptidase activity on the carbonyl-donor/amino-acceptor tetrapeptide ACLLys(Gly)-DAla-DAla. The exocellular 40 000-Mr enzyme and the two lysozyme-releasable 40 000-Mr and 38 000-Mr enzymes are moderately sensitive to benzylpenicillin and have a high propensity to catalyse dimer formation from the aforementioned tetrapeptide monomer.

A 58-year-old Caucasian man was receiving long-term anticoagulation with warfarin for the prevention of ischemic stroke; his international normalized ratio (INR) had been stable. His INR increased when he began consistent, low-dose beer consumption for its perceived cardiovascular protection. After he stopped drinking the alcohol, his anticoagulation control improved and returned to previous levels. Information on the effects of alcohol, particularly beer, is limited in nonalcoholic patients who receive warfarin therapy. This case reveals a potential for low-dose beer consumption to elevate INR. We propose that the increased antithrombotic effect of warfarin involved protein-binding interactions and decreased warfarin metabolism through the cytochrome P450 (CYP) enzyme system. Concurrent administration of aspirin and other drugs that are metabolized through or are inhibitors of the CYP system may have enhanced the interaction that occurred in this patient. Caution should be used whenever warfarin and alcohol in any amount are taken together, especially in patients receiving many drugs, and close monitoring of the INR is warranted.

St. John's wort (Hypericum perforatum) is one of the best-selling herbal remedies in the United States. It has been implicated as an inducer of the P450 enzyme system, and as such, may cause increased metabolism of certain drugs, including oral contraceptives. Women using oral contraceptives have been warned against using St. John's wort. To date, there are some case reports but little clinical data demonstrating risk of contraceptive failure if they do. This article reviews available data and discusses theoretical reasons for concern about possible drug-herb interactions.

This review covers various aspects of studies, which were done to develop processes to make products that resemble traditional/processed cheese without the use of micro-organisms or enzyme system. Several manufacturing techniques and incorporation of various ingredients/additives, examples of which are emulsifying salts, texture modifiers and flavour enhancers, in the formulations are discussed. Characteristics like rheology, chemical composition, biochemical changes and microstructure of such products are also given.

Glycogen storage disease type I is an autosomal recessive disorder caused by the defect in the glucose-6-phosphate enzyme system. Frequent intake of glucose-containing glycogen storage disease formula, uncooked cornstarch, or both, are usually needed to maintain normal blood glucose level. We report a glycogen storage disease type 1b girl with biotin deficiency caused by an exclusive glucose-containing glycogen storage disease formula for years, presenting with the appearance of severe skin lesions, and diagnosed by urinary organic acid analysis by gas chromato-spectrometry, and blood acylcarnitine analysis by tandem mass-spectrometry.

The effect of a new cold-active pectinolytic system on colour of Malbec wines was studied under the following winemaking conditions: (i) fermentation at low temperature (20 °C) and (ii) prefermentative cold maceration (PCM) (5 °C–7 days) followed by traditional fermentation (28 °C). The pectinolytic system was mainly composed of polymethylgalacturonase and pectin lyase activities, detected under similar conditions to those in winemaking (pH 3.6–20 °C). The results show that the enzyme system significantly accelerated colour extraction by reducing the maceration time necessary for vinification at low temperature and shortening the PCM stage. Enzyme-treated wines exhibited better chromatic parameters than their controls at devatting and after 6 months of storage. The cold-active enzyme compensated the decrease in colour extraction due to the low maceration temperature, achieving high-quality wines with chromatic characteristics similar to those of traditional wines. Fil: Martín, María Carolina. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina Fil: Morata, Vilma Ines. Universidad Nacional de Cuyo. Facultad de Ciencias Aplicadas a la Industria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina

Early studies used extremely overheated fats which were toxic if fed to animals. Later fats and oils were heated in equipments for deep-fat frying under the conditions of good commercial practice. Such heated fats showed no detrimental effects even if fed in long-term feeding trials. The results are reported and critically evaluated. However, certain fractions of the heated fats, e.g. the so called Total Polar Materials caused clearly noticeable effects in the feeding studies: growth retardation, increased liver and kidney weights, and disorders of the enzyme system but only if fed in high doses. In the last years several research groups specialized in the use of cell cultures and enzymo-logical methods and gained insight into resorption and metabolism. Model compounds or compound mixtures have been synthesized. Their structure and/or composition deviated more or less from the genuine compounds or fractions of the heated fats and the results of these studies must not be generalized. New analytical procedures allow to isolate well-defined fractions, and quantitative data about their contents in heated fats are obtained: (a) harmless mono- and diglycerides and free fatty acids, (b) dimeric and polymeric triglycerides and dimeric fatty acids, harmless as well because of very low resorption rates and (c) oxidized triglyceride monomers. Their saponification and degradation products are oxidized monomeric and dimeric acids, oxidized cyclic fatty acids, and other polar compounds. These low molecular oxidized compounds are nutritionally suspect. Since 60 years and with considerable effort more or less systematic investigations have been performed in many countries to answer the question, if heated fats are detrimental to health.

The ability of Streptomyces griseoviridis (strain Tu 3634) to glycosylate various carboxylic acids with L-rhamnose was investigated by feeding mainly heteroaromatic and aromatic carboxylic acids to growing cultures. The special application of the precursor-directed biosynthesis (PDB) gave rise to a wide variety of acyl α-L-rhamnopyranosides as novel metabolites. The experiments resulted in furanyl, pyrrolyl, thienyl, indolyl, and pyridyl derivatives (1−8), the analogues 9−24 were generated by feeding fluoro-, hydroxy- or aminobenzoic acids or cinnamic acids. All results are discussed with respect to the substrate specificity of the corresponding enzyme system.

Ferguson plots, linear regressions of log(relative mobility) against polyacrylamide gel concentration, provide an electrophoretic method of simultaneously obtaining estimates of net charge and molecular weight for nondenatured proteins, and are a powerful method of accurately comparing these characteristics among isozymes within an enzyme system. Here, Ferguson plots compare the characteristics of the nine isozymes (three cationic and six anionic) usually seen in soluble extracts of flax (Linum usitatissimum) seedling tissues, and of five anionic isozymes induced by heavy metal stress. Despite some differences in apparent molecular weight, all but one of the isozymes separated from each other on the basis of net charge and, except for a second isozyme with a comparatively high molecular weight, the net charges of the isozymes ranked in order of their relative mobilities on nondenaturing gels. Differences among the isozymes make it unlikely that any are related, which indicates that they are encoded by different structural genes.

A biphasic system containing NADPH and glucose with a cell-free extract of a recombinant E.

An adaptive lattice filter for filtering impulsive noise is designed using a cyclic enzyme system. The cyclic enzyme system has a memory mechanism and can maintain the previous output for some duration independently of the system input. The partial autocorrelation (PARCOR) coefficient computed through the system is then robust against impulsive noise that appears as large spikes of short duration. Furthermore, a set of PARCOR coefficients estimated by the new filter is always stable. The effectiveness is investigated analytically and through computer simulation.

Many kinds of aromatic nitriles have been hydrolyzed to afford the corresponding amides and carboxylic acids, by the aid of enzyme system of Rhodococcus butanica. This enzymatic hydrolysis can be successfully applied to the kinetic resolution of α-arylpropionitriles, resulting in the formation of (R)-amides and (S)-carboxylic acids.

Fortheoxidationofalcohols that require nicotinamide adenine nucleotide(NAD)oritsphosphateanalogue(NADP),orthereduc-tionofcarbonylcompoundsmediatedbythereducedformNADH(NADPH),regenerationofthecofactorisneces-sary. EnzymaticregenerationofNADH(orNADPH)forsynthesis usually employs the glucose/glucose dehy-drogenase

Yamadazyma farinosa IFO 10896 was found to reduce α-hydroxyketones bearing a phenyl ring to give optically active diols with anti-Prelog selectivity. The distance between the carbonyl group and the phenyl ring was shown to have an interesting effect on the reactivity and selectivity of the enzyme system.

An enzyme system of Nocardia diaphanozonaria JCM 3208 catalyzes the inversion of the chirality of various α-substituted carboxylic acids, such as 2-phenylpropanoic acid and 2-phenoxypropanoic acid derivatives, via a novel deracemization reaction.

The coupled bioluminescent enzyme system luciferase–NADH:FMN-oxidoreductase was used as a biotest in ecological monitoring of the health resort salt lake Shira (South Siberia, Russia). The technique was adapted to saltwater conditions. Bioluminescence kinetic parameters sensitive to pollutants were determined. Conditions for the use of bacterial bioluminescence biotests in salty environmental media were established. Copyright © 1999 John Wiley & Sons, Ltd.

The total synthesis, at will, of a wide variety of protein and enzyme molecules is made feasible by modem chemical ligation methods. As Emil Fischer intuitively understood, synthetic access to the enzyme molecule enables the power of chemical science to be applied to elucidating the molecular basis of catalytic function in unprecedented detail.

The plasminogen activation system is a vertebrate extracellular enzyme system consisting of serine proteinases, proteinase inhibitors of the serpin family, and various binding proteins. The plasminogen activation system generates extracellular proteolytic activity for physiological and pathophysiological fibrinolysis and tissue remodelling. Keywords: plasminogen activators; tPA; uPA; fibrinolysis; tissue remodelling

Heat inactivation studies were conducted on the ethylene-forming enzyme system (EFE) in papayas of different maturities, and at three tissue depths. D-values showed EFE in the mesocarp and endocarp were more heat sensitive than EFE in the exocarp. Within the mesocarp and endocarp, EFE in ¼ and ½ ripe papayas were more heat labile than in mature green and color break fruits. Ion leakage increased concomitantly with increased mesocarp and endocarp ripeness confirming that papayas ripen differentially from the innermost tissues outwards. Membrane integrity as determined by ion leakage may explain the increase in heat sensitivity of EFE in riper tissues.

The relation between photosynthesis and water content was investigated using detached leaves of Populus euramericana (Dode) Guinier cv. Robusta. The time course of photosynthesis was measured at different light intensities, at different CO2 contents of the air and at constant temperature during the desiccation of the leaves. The time course of decreasing water content was obtained from continuous measurement of water transpired from the leaves. A large reduction of light saturated (400 W × m−2) photosynthetic rates was observed with decreasing water contents between 78 and 64% (water potential between −14 and −24 atm (bar)). This reduction was much greater in air with 0.3 % CO2 than in air with 5 % CO2, indicating a significant influence of CO2 diffusion resistance on rate of photosynthesis. The reduction of the rate of light and CO2 saturated photosynthesis (at 400 W × m–2 and 5% CO2 in the air) is a measure of the inactivation of the photosynthetic enzyme system by desiccation. A proportional reduction of the light saturated and light limited rate of photosynthesis (for different H2O contents) was found, when measured in air containing a saturating amount of CO2 (5 %). The reduction of the light limited rate of photosynthesis (at 20 W × m−2) was the same at both CO2 levels.

The progesterone 11α-hydroxylase of Rhizopus nigricans ATCC 6227b is an inducible enzyme system that is primarily induced by its substrate progesterone. Maximum induction was found at a progesterone concentration of 0.5 g/liter or above. Oxygen is the other substrate for the hydroxylation and this was found to have a major effect on the amounts of hydroxylase synthesized. Optimum induction of the hydroxylase in a fermentation with a 3.1 m/sec impeller tip speed was found to occur at a dissolved oxygen tension (DOT) of 10% of air saturation. The agitation rate also effects the amount of hydroxylase synthesized with an apparent maximum at 3.1 m/sec impeller tip speed. The DOT for a maximum hydroxylation rate was much higher than for enzyme synthesis so that it was preferable to increase the DOT after induction was completed.

An active lipid peroxidizing enzyme system was investigated in microsomal fractions isolated from the gonad and hepatopancreatic tissue of live cultivated mussels. Enzyme-mediated lipid peroxidation was detected in gonad microsomes and was shown to be dependent upon the presence of NADH, ADP, and Fe3+ ions. A marked increase in the peroxidizing capacity of gonadal microsomes was observed following lipid emulsion loading. Fresh microsomes prepared from hepatopancreatic tissue showed no detectable levels of lipid peroxidizing activity. However, freeze-thaw treatment of microsomes from both gonadal and hepatopancreatic tissues resulted in an initiation of activity in the hepatopancreatic tissue and increased the existing activity of the gonad microsomes.

The stabilities and optima with respect to temperature and pH of the β-glucosidase, Avicelase, and carboxymethylcellulase (CMCase) activity of Thermomonospora sp., in the culture filtrate, culture whole broth, and filtrate after sonication of culture solids, are reported. The β-glucosidase is cell associated and has an optimal activity at about pH 6.5 and 55°C. In the whole culture broth, it has a half-life of about 8 hr at 55°C and less than 1 hr at 60°C, while the half-life of the activity in the sonicated, cell-free filtrate is less than 1 hr at 55°C. The Avicelase and CMCase activities occur in the extracellular culture fluid and have optima at about pH 7.0 and 5.9, and 65 and 70°C, respectively. The CMCase activity is stable over 24 hr at 60°C, but declines by 50% in the same period at 65°C. The Avicelase activity declines by 15% over 24 hr at 55°C, and by 50% at 60°C. The highest pH studied (pH 7.3) was the most destabilizing for all three activities. The thermostable characteristics of the cellulases from Themomonospora appear to make them suitable for commercial saccharification processes operating at elevated temperatures.

An enzyme system that converts α-ecdysone to its hormonally less active 3α-epimer was detected only in the midgut of the tobacco hornworm,Manduca sexta (L.). This system appears to be specific for the ecdysones and may represent a metabolic control point for regulating molting hormone activity.

The inhibition constants (KI) of aliphatic and aromatic amide derivatives of phenylalanine and proline for GS1 and GS2 of the enzyme system gramicidin S synthetase were determined. These compounds act as competitive inhibitors. Some of these compounds (spacer/ligand compounds) were reacted with epoxy-activated Sekpharose 6B or with crosslinked poly(vinyl alcohol). The resulting—for GS1 or GS2 more or less specific—adsorption materials, were used for the purification of these multi-enzyme systems.

EMD-IT-5914 (5-dimethylamino-methylene-2-oxo-4-phenyl-2,5-dihydrofurane-carbonitril-(3)) inhibited chlorophyll a formation almost completely and chlorophyll b and total carotenoids up to 80% of the control, but did not appreciably affect the activity of the enzyme system succinyl-CoA synthetase/δ-aminolevulinic acid synthetase. The activity of δ-aminolevulinic acid dehydratase was not found limiting. In contrast, the herbicide strongly inhibited the activity of porphobilinogenase, and the reaction kinetics pointed towards a non-competitive type of inhibition. The results are discussed in relation to the possible role of EMD-IT-5914 in chlorophyll biosynthesis.

Lactoperoxidase catalyzes the oxidation of thiocyanate by hydrogen peroxide and an intermediary product is formed with antibacterial properties. The components of this system, with the exception of hydrogen peroxide, are present in milk. H2O2 may be introduced by means of enzymatic, generation and thus make the system complete. A two-enzyme system consisting of β–galactosidase and glucose oxidase has been developed for this purpose. The coupled enzyme reaction is shown to work with high efficiency at the neutral pH of milk although the enzymes as such, particularly lactases suitable for immobilization, have optimal activities at much lower pH values. The results indicate that the lactoperoxidase system may in this way be employed to inactivate bacteria present in milk.

Bei der Herstellung von Ethanol aus starkehaltigen Rohstoffen nach drucklosen Starkeaufschlusverfahren ist die erreichbare Alkoholausbeute wesentlich vom Zerkleinerungsgrad des Rohstoffes, von der Quellung, der thermischen Behandlung zur Verkleisterung, Losung und zum enzymatischen Abbau der Starke sowie von der Art des verwendeten Enzymsystems abhangig. Eine isolierte Betrachtung der einzelnen Prozesparameter ist infolge ihrer gegenseitigen Abhangigkeit nicht moglich. Von uberragender Bedeutung ist dabei das eingesetzte Enzymsystem, das uber den Einflus der anderen Prozesparameter in erheblichem Umfange zu dominieren vermag. Von den untersuchten Enzympraparaten erwies sich ein aus Rhizopus spec. hergestelltes Praparat hinsichtlich seiner Unempfindlichkeit gegenuber den Prozesparametern Zerkleinerungsgrad des Rohstoffes und Quellung sowie auch des Energiebedarfes fur die thermische Behandlung als deutlich uberlegen. Production of Ethanol from Wheat. Research on the Pressure-free Starch Decomposition Process (DSA-Process). In the production of ethanol from starch-containing raw materials by pressure-free starch decomposition processes the attainable alcohol yield is significantly dependent on the degree of shredding of the raw material, on steeping, on thermal treatment for pasting, solving and enzymatic degradation of the starch, as well as on the kind of enzyme system used. An isolated appreciation of the individual process parameters is not possible due to their interaction. The enzyme system used is of major importance, which is able to dominate the influence of the other process parameters to a significant degree. Of all the enzyme preparations studied one preparation derived from Rhizopus spec. (Optilase G 150®) proved to be clearly superior regarding its immunity to the process parameters of degree of shredding of raw material, and steeping as well as energy consumption for thermal treatment.

Metyrapone (1) and metyrapol (2) are potent and reversible inhibitors of the 11β-hydroxylase enzyme system of the adrenal cortex. Iodine-125-labelled derivatives of 1 and 2 were required for biodistribution studies. Utilizing a new exchange procedure these radioiodinated analogues were synthesized with radiochemical yields ranging from 24-100% and specific activities as high as 1.72 Ci/mmol.

Aromatic carboxylic acids strongly inhibited 4-methylcatechol oxidation by an o-diphenol oxidase extracted from sweet cherry fruits (Prunus avium). Esterification of the acids decreased their inhibitory strength. Inhibitors containing the benzene nucleus showed a greater effectiveness than the corresponding aliphatic and heterocyclic compounds (except 2-naphthalenecarboxylic acid). Similar inhibitory effects were observed by replacing the benzene ring with a highly unsaturated open chain. The inhibitory properties of benzoic acid, cinnamic acid, p-coumaric acid and 3,4-dihydroxybenzoic acid were investigated. It is proposed that the catalytic and inhibitory sites are close together in the enzyme molecule.

The pharmacokinetics and relative systemic availability or oral propranolol were studied in three healthy volunteers following administration of 10, 40, and 80 mg of propranolol hydrochloride. Plasma concentrations of propranolol were determined using a sensitive and specific fluorometric high pressure liquid chromatographic technique. In the dosage range studied, the amount of propranolol reaching the systemic circulation increased with dose, while half-lives remained unchanged. The apparent 'threshold dose' for propranolol was much smaller than previously reported, and its contribution to the observed dose-dependent availability is doubtful. Apparent intrinsic clearance values were shown to decrease with increase in dose, with a true maximal intrinsic clearance of 5.4 l kg-1 h-1. These data suggest the saturation of a low capacity enzyme system in the liver and are consistent with theoretical characteristics of a drug that is extensively metabolized during its first pass through the liver.