Immobilization is an exciting alternative to improve the stability of enzymatic processes. However, part of the applied covalent strategies for immobilization uses specific conditions, generally alkaline pH, where some enzymes are not stable. Here, a new generation of heterofunctional supports with application at neutral pH conditions was proposed. New supports were developed with different bifunctional groups (i.e., hydrophobic or carboxylic/metal) capable of adsorbing biocatalysts at different regions (hydrophobic or histidine richest place), together with a glutaraldehyde group that promotes an irreversible immobilization at neutral conditions. To verify these supports, a multi-protein model system (E. coli extract) and four enzymes (Candida rugosa lipase, metagenomic lipase, β-galactosidase and β-glucosidase) were used. The immobilization mechanism was tested and indicated that moderate ionic strength should be applied to avoid possible unspecific adsorption. The use of different supports allowed the immobilization of most of the proteins contained in a crude protein extract. In addition, different supports yielded catalysts of the tested enzymes with different catalytic properties. At neutral pH, the new supports were able to adsorb and covalently immobilize the four enzymes tested with different recovered activity values. Notably, the use of these supports proved to be an efficient alternative tool for enzyme immobilization at neutral pH.

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder worldwide. Currently, the only strategy for palliative treatment of AD is to inhibit acetylcholinesterase (AChE) in order to increase the concentration of acetylcholine in the synaptic cleft. Evidence indicates that AChE also interacts with the β-amyloid (Aβ) protein, acting as a chaperone and increasing the number and neurotoxicity of Aβ fibrils. It is known that AChE has two binding sites: the peripheral site, responsible for the interactions with Aβ, and the catalytic site, related with acetylcholine hydrolysis. In this work, we reported the synthesis and biological evaluation of a library of new tacrine-donepezil hybrids, as a potential dual binding site AChE inhibitor, containing a triazole-quinoline system. The synthesis of hybrids was performed in four steps using the click chemistry strategy. These compounds were evaluated as hAChE and hBChE inhibitors, and some derivatives showed IC 50 values in the micro-molar range and were remarkably selective towards hAChE. Kinetic assays and molecular modeling studies confirm that these compounds block both catalytic and peripheral AChE sites. These results are quite interesting since the triazole-quinoline system is a new structural scaffold for AChE inhibitors. Furthermore, the synthetic approach is very efficient for the preparation of target compounds, allowing a further fruitful new chemical library optimization.

A chemical study of the EtOAc extract of Nemania bipapillata (AT-05), an endophytic fungus isolated from the marine red alga Asparagopsis taxiformis - Falkenbergia stage, led to the isolation of five new botryane sesquiterpenes, including the diastereomeric pair (+)-(2 R ,4 S ,5 R ,8 S )-( 1 ) and (+)-(2 R ,4 R ,5 R ,8 S )-4-deacetyl-5-hydroxy-botryenalol ( 2 ), (+)-(2 R ,4 S ,5 R ,8 R )-4-deacetyl-botryenalol ( 3 ), one pair of diastereomeric botryane nor sesquiterpenes bearing an unprecedented degraded carbon skeleton, (+)-(2 R ,4 R ,8 R )-( 4 ) and (+)-(2 R ,4 S ,8 S )-( 5 ), which were named nemenonediol A and nemenonediol B, respectively, in addition to the known 4β-acetoxy-9β,10β,15α-trihydroxyprobotrydial ( 6 ). Their structures were elucidated using 1D and 2D NMR, HRESIMS and comparison with literature data of similar known compounds. The absolute configurations of 2 , 3 and 4 were deduced by comparison of experimental and calculated electronic circular dichroism (ECD) spectra, while those of 1 and 5 were assigned from vibrational circular dichroism (VCD) data. Compound 4 weakly inhibited acetylcholinesterase, whereas compound 1 inhibited both acetylcholinesterase and butyrylcholinesterase. Compounds 1 , 3 , 5 and 6 were tested against two carcinoma cell lines (MCF-7 and HCT-116), but showed no significant citotoxicity at tested concentrations (IC 50 > 50 µM).

The enzyme β-secretase1 (BACE1) initiates the cleavage of the Ab amyloid precursor protein (APP), to generate and aggregate β-amyloid (Ab) peptides, which are implicated in the pathogenesis of Alzheimer's disease (AD). Herein, a BACE1 immobilised capillary enzyme reactor (ICER) attached to a mass spectrometer for the on-flow screening of ligands was prepared.

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