The biomineralisation of metal phosphates is a promising approach to develop more efficient nanobiocatalysts; elucidating which protein regions most likely participate in the mineral formation will guide the fabrication of more efficient biocatalysts based on metal-phosphate nanoflowers.

The human mitochondrial peptide deformylase (HsPDF) provides a potential new target for broadly acting antiproliferative agents. To identify novel nonpeptidomimetic and nonhydroxamic acid-based inhibitors of HsPDF, the authors have developed a high-throughput screening (HTS) strategy using a fluorescence polarization (FP)-based binding assay as the primary assay for screening chemical libraries, followed by an enzymatic-based assay to confirm hits, prior to characterization of their antiproliferative activity against established tumor cell lines. The authors present the results and performance of the established strategy tested in a pilot screen of 2880 compounds and the identification of the 1st inhibitors. Two common scaffolds were identified within the hits. Furthermore, cytotoxicity studies revealed that most of the confirmed hits have antiproliferative activity. These findings demonstrate that the designed strategy can identify novel functional inhibitors and provide a powerful alternative to the use of functional assays in HTS and support the hypothesis that HsPDF inhibitors may constitute a new class of antiproliferative agent.

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In situ immobilization of β-galactosidase from Bacillus circulans in silica by sol-gel process: Application in prebiotic synthesisThe enzyme encapsulation is a very well-known stabilization pathway. However, there are some challenges in order to avoid the enzyme denaturation under encapsulation conditions. The β-galactosidase from Bacillus circulans was immobilized through sol-gel encapsulation route assisted by Triton X-100 surfactant and sugars. The effects of sugar presence in the immobilization process and the gelation time on the biocatalyst activity/stability were explained taking into account the characteristics of the formed silica matrix and the changes of the enzyme environment. The enzyme was effectively immobilized by this strategy, with high immobilization yield in terms of activity (29%) and expressed activity (47 IU/g). The immobilization through silica sol-gel in the presence of 1×10 −3 M Triton X-100 and fructose conferred 28.4-fold higher stability to the enzyme compared with the soluble form. This is an advantage for its use in the synthesis of the galacto-oligosaccharides at 50˚C. The total lactose conversion to galacto-oligosaccharides was 26%wt, which is comparable with that reported in the literature. The obtained biocatalyst is useful for the synthesis of galacto-oligosaccharides and its catalytic behavior is rationalized in this work. IntroductionThe β-galactosidase from Bacillus circulans is a hydrolase (E.C.

The sol-gel process has been very useful for preparing active and stable biocatalysts, with the possibility of being reused. Especially those based on silica are well known. However, the study of the enzyme behavior during this process is not well understood until now and more, if the surfactant is involved in the synthesis mixture. This work is devoted to the encapsulation of β-galactosidase from Bacillus circulans in silica by sol-gel process, assisted by non-ionic Triton X-100 surfactant. The correlation between enzyme activity results for the β-galactosidase in three different environments (soluble in buffered aqueous reference solution, in the silica sol, and entrapment on the silica matrix) explains the enzyme behavior under stress conditions offered by the silica sol composition and gelation conditions. A stable β-galactosidase/silica biocatalyst is obtained using sodium silicate, which is a cheap source of silica, in the presence of non-ionic Triton X-100, which avoids the enzyme deactivation, even at 40 °C. The obtained biocatalyst is used in the whey hydrolysis for obtaining high value products from this waste. The preservation of the enzyme stability, which is one of the most important challenges on the enzyme immobilization through the silica sol-gel, is achieved in this study.

Chitosan was derivatized by two methodologies for analyzing their effect on chitosan physicochemical characteristics and its applicability as carrier for Bacillus circulans b-galactosidase immobilization. Glutaraldehyde (GA) and epichlorohydrin (EPI) were used for crosslinking and activation of chitosan, producing the corresponding supports (C-GA and C-EPI-EPI) after a one-step and a twostep process, respectively. The spherical shape and mean diameter of chitosan particles was not significantly affected by polymer derivatization, while Fourier transform infrared analysis showed that in both cases, chitosan polymer was chemically modified. TGA analysis indicated that C-EPI-EPI was the most thermally stable. The high degree of activation of C-EPI-EPI (586 lmol of aldehydes/g) resulted in the highest loss of activity during immobilization; hence a support with 100 lmol of aldehydes/g was produced (C-EPI-EPI 100 ). The highest expressed activity (89.3 IU/g) was obtained with the enzyme immobilized in C-GA, while the biocatalyst with highest thermal stability at 60 C was obtained with C-EPI-EPI 100 (half-life was 84-fold higher than the one of the soluble enzyme). The best compromise between biocatalyst expressed activity and thermal stability corresponded to b-galactosidase immobilized in C-EPI-EPI 100 . According to this study, chitosan derivatized with EPI is a thermally stable carrier appropriate for producing highly stable immobilized B. circulans b-galactosidase. V C 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40171.

Ionizing radiation (IR) and certain chemotherapeutic drugs are designed to generate cytotoxic DNA double-strand breaks (DSBs) in cancer cells. Inhibition of the major DSB repair pathway, nonhomologous end joining (NHEJ), will enhance the cytotoxicity of these agents. Screening for inhibitors of the DNA ligase IV (Lig4), which mediates the final ligation step in NHEJ, offers a novel target-based drug discovery opportunity. For this purpose, we have developed an enzymatic assay to identify chemicals that block the transfer of [a- Rabeprazole and U73122 were found to specifically block the adenylate transfer step and DNA rejoining; in whole live cell assays, these compounds were found to inhibit the repair of DSBs generated by IR. The ability to screen and identify Lig4 inhibitors suggests that they may have utility as chemo-and radio-sensitizers in combination therapy and provides a rationale for using this screening strategy to identify additional inhibitors.

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