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91.
N Tibrewal TE Downey SG Van Lanen E Ul Sharif GA O'Doherty J Rohr 《Journal of the American Chemical Society》2012,134(30):12402-12405
Two enzymes of the gilvocarcin biosynthetic pathway, GilMT and GilM, with unclear functions were investigated by in vitro studies using purified, recombinant enzymes along with synthetically prepared intermediates. The studies revealed GilMT as a typical S-adenosylmethionine (SAM) dependent O-methyltransferase, but GilM was identified as a pivotal enzyme in the pathway that exhibits dual functionality in that it catalyzes a reduction of a quinone intermediate to a hydroquinone, which goes hand-in-hand with a stabilizing O-methylation and a hemiacetal formation. GilM mediates its reductive catalysis through the aid of GilR that provides FADH(2) for the GilM reaction, through which FAD is regenerated for the next catalytic cycle. This unusual synergy eventually completes the biosynthesis of the polyketide-derived defuco-gilvocarcin chromphore. 相似文献
92.
The ground state geometries of [Alanine (Ala) + M2+] [M = Ca, Cu, and Zn) complexes were calculated in gas phase at B3LYP/6‐311++G(d,p) level of theory. Transition states (TSs) between different stable conformers of [Ala + M2+] complexes were also calculated. Among the different [Ala + M2+] complexes, the complex where metal cations coordinated to carboxylate group (? COO?) is found to be energetically most favorable. To calculate TSs, the ground state structures of any two conformers of [Ala + M2+] complexes were used. The ground state energies of two stable conformers and their TS structures were used to calculate the activation energy. The reactivity of different conformers of [Ala + M2+] complexes have been discussed in terms of energy difference between their highest occupied molecular orbital and lowest unoccupied molecular orbital. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 相似文献
93.
94.
Pallavi Dwivedi V. Vivekanand Nidhi Pareek Amit Sharma Rajesh P. Singh 《Applied biochemistry and biotechnology》2010,160(1):255-268
Mixed enzyme preparation having both xylanase and laccase activity was evaluated for its bleach enhancing ability of mixed
wood pulp. The enzyme was produced through co-cultivation of mutant Penicillium oxalicum SAUE-3.510 and Pleurotus ostreatus MTCC 1804 under solid-state fermentation. Bleaching of pulp with mixed enzyme had resulted into a notable decrease in kappa
number and increased brightness as compared to xylanase alone. Analysis of bleaching conditions had denoted that 8 IU g−1 of mixed enzyme preparation (xylanase/laccase, 22:1) had led into maximal removal of lignin from pulp when bleaching was
performed at 10% pulp consistency (55 °C, pH 9.0) for 3 h. An overall improvement of 21%, 8%, 3%, and 5% respectively in kappa
number, brightness, yellowness, and viscosity of pulp was achieved under derived bleaching conditions. Process of enzymatic
bleaching was further ascertained by analyzing the changes occurring in polysaccharide and lignin by HPLC and FTIR. The UV
absorption spectrum of the compounds released during enzymatic treatment had denoted a characteristic peak at 280 nm, indicating
the presence of lignin in released coloring matter. The changes in fiber morphology following enzymatic delignification were
studied by scanning electron microscopy. 相似文献
95.
A new method to study families of finite sets, in particular t-designs, by studying families of multisets (also called lists) and their relationships with families of sets, is developed. Notion of the tag for a subset defined earlier by one of the authors is extended to a submultiset. A new concept t-(v, k, λ) list design is defined and studied. Basic existence theory for designs is extended to a new set up of list designs. In particular tags are used to prove that signed t-list designs exist whenever necessary conditions are satisfied. The concepts of homomorphisms and block spreading are extended to this new set up. 相似文献
96.
Nanotechnology can be described as an emerging technology and, as has been the case with other emerging technologies such
as genetic modification, different socio-psychological factors will potentially influence societal responses to its development
and application. These factors will play an important role in how nanotechnology is developed and commercialised. This article
aims to identify expert opinion on factors influencing societal response to applications of nanotechnology. Structured interviews
with experts on nanotechnology from North West Europe were conducted using repertory grid methodology in conjunction with
generalized Procrustes analysis to examine the psychological constructs underlying societal uptake of 15 key applications
of nanotechnology drawn from different areas (e.g. medicine, agriculture and environment, chemical, food, military, sports,
and cosmetics). Based on expert judgement, the main factors influencing societal response to different applications of nanotechnology
will be the extent to which applications are perceived to be beneficial, useful, and necessary, and how 'real' and physically
close to the end-user these applications are perceived to be by the public. 相似文献
97.
Feliu Elisenda Kaihnsa Nidhi de Wolff Timo Yürük Oğuzhan 《Journal of Dynamics and Differential Equations》2022,34(2):825-852
Journal of Dynamics and Differential Equations - Multistationarity in molecular systems underlies switch-like responses in cellular decision making. Determining whether and when a system displays... 相似文献
98.
Pure and ZnCl2 doped anthracene (AN & ANZ) single crystals were grown by the slow evaporation method. In XRD studies a shift in peaks towards higher theta value and change in preferred orientation from (0 0 1) to (0 0 2) were observed as a result of doping. UV-vis spectra show a blueshift of various peaks in ANZ. Remarkable increases in dielectric constant and AC conductivity were observed along with a structure related phase transition at 40 °C in ANZ at atmospheric pressure itself. Good fluorescence properties with a strong green emission were observed in photoluminescence studies. 相似文献
99.
Photogalvanic effects were studied in photogalvanic cells containing sodium lauryl sulphate as surfactant, EDTA as reductant
and azur-B as photosensitizer. The photopotential and photocurrent generated were 814#x00B7;0 mV and 255·0 μA respectively.
The observed conversion efficiency was 1·2% and the maximum power of cell was 207·57 μW. The storage capacity of the cell
was 26#x00B7;0 min in dark. The effect of different parameters on electrical output of the cell was observed. A mechanism
has been proposed here for the generation of photocurrent in photogalvanic cells 相似文献
100.
Gupta N Gupta R Chandra S Bawa SS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(6):1175-1180
A series of new mono and binuclear copper (II) complexes [Cul]X(2)and [Cu(2)lX(2)] where 1 = L(1), L(2) and L(3) are the macrocyclic ligands. In mononuclear complexes the geometry of Cu(II) ion is distorted squareplanar and in binuclear complexes the geometry of Cu(II) is tetragonal. The synthesized complexes were characterized by spectroscopic (IR,UV-vis and ESR) techniques. Electrochemical studies of the complexes reveals that all the mononuclear Cu(II) complexes show a single quasireversible one-electron transfer reduction wave (E(pc) = -0.76 to -0.84V) and the binuclear complexes show two quasireversible one electron transfer reduction waves (E(pc)(1) = -0.86 to -1.01V, E(pc)(2) = -1.11 to -1.43V) in cathodic region. The ESR spectra of mononuclear complexes show four lines with nuclear hyperfine splittings with the observed g(11) values in the ranges 2.20-2.28, g( perpendicular) = 2.01-2.06 and A(11) = 125-273. The binuclear complexes show a broad ESR spectra with g = 2.10-2.11. The room temperature magnetic moment values for the mononuclear complexes are in the range [mu(eff) = 1.70-1.72BM] and for the binuclear complexes the range is [mu(eff) = 1.46-1.59BM]. 相似文献