Immobilization of Prunus amygdalus Hydroxynitrile Lyase on Celite

The hydroxynitrile lyase from Prunus amygdalus was immobilized on Celite R-633. The immobilized enzyme could successfully be utilized in buffer saturated MTBE and excellent conversions of benzaldehyde to R-mandelonitrile were observed. No leaching occurred. To achieve high enantioselectivities, the suppression of the undesired background reaction was essential. This could be achieved by high enzyme loadings and the tight packing of the immobilized enzymes. When the immobilized enzyme is loosely packed, both the enzyme catalysis and the background reaction accelerates and only a modest enantioselectivity is observed. The enzyme was recycled for up to ten times, with some loss of activity and also enantioselectivity after 5 cycles, independent of packing.BT/Biocatalysi

MsAcT in siliceous monolithic microreactors enables quantitative ester synthesis in water

Acyltransferase from Mycobacterium smegmatis (MsAcT) immobilised in continuous-flow microchannel (30-50 ?m dia.) reactors with hierarchical pore structure (4 cm3/g total pore volume) enabled quantitative, full and rapid transesterification of neopentylglycol with ethyl acetate in a biphasic 50/50 % system in less than one minute. MsAcT was attached either covalently via amino groups or by a specific His-tag-mediated adsorption on Ni or Co sites. Both methods gave similar results for enzyme loading (ca.3 mg/g of carrier, 60-70 % immobilisation yield) and specific activity. The experiments revealed that the rate of monoester formation in the microreactor was exceedingly fast compared to that of diester synthesis and also the native enzyme behaviour in batch reactor. The studies show that the course of transesterification was fully controlled by biocatalytic properties of MsAcT confined in the mesoporous environment. These findings may be of significant interest from both fundamental and practical perspective.BiotechnologyApplied Science

Preclinical evaluation of binimetinib (MEK162) delivered via polymeric nanocarriers in combination with radiation and temozolomide in glioma

Background and purpose: Glioblastoma multiforme (GBM) is the most aggressive subtype of malignant gliomas, with an average survival rate of 15 months after diagnosis. More than 90% of all GBMs have activating mutations in the MAPK/ERK pathway. Recently, we showed the allosteric MEK1/2 inhibitor binimetinib (MEK162) to inhibit cell proliferation and to enhance the effect of radiation in preclinical human GBM models. Because the free drug cannot pass the blood–brain barrier (BBB), we investigated the use of nanocarriers for transport of the drug through the BBB and its efficacy when combined with radiotherapy and temozolomide (TMZ) in glioma spheroids. Methods: In vitro studies were performed using multicellular U87 human GBM spheroids. Polymeric nanocarriers (polymersomes) were loaded with MEK162. The interaction between nanocarrier delivered MEK162, irradiation and TMZ was studied on the kinetics of spheroid growth and on protein expression in the MAPK/ERK pathway. BBB passaging was evaluated in a transwell system with human cerebral microvascular endothelial (hCMEC/D3) cells. Results: MEK162 loaded polymersomes inhibited spheroid growth. A synergistic effect was found in combination with fractionated irradiation and an additive effect with TMZ on spheroid volume reduction. Fluorescent labeled polymersomes were taken up by human cerebral microvascular endothelial cells and passed the BBB in vitro. Conclusion: MEK162 loaded polymersomes are taken up by multicellular spheroids. The nanocarrier delivered drug reduced spheroid growth and inhibited its molecular target. MEK162 delivered via polymersomes showed interaction with irradiation and TMZ. The polymersomes crossed the in vitro BBB model and therewith offer exciting challenges ahead for delivery of therapeutics agents to brain tumours.RST/Applied Radiation & IsotopesRST/Technici PoolChemE/Advanced Soft Matte