Schiff bases attract research interest due to their applications in chemical synthesis and medicinal chemistry. In recent years, benitrobenrazide and benserazide containing imine moiety, have been synthesized and characterized as promising inhibitors of hexokinase 2 (HK2) an enzyme overexpressed in most cancer cells. Both compounds possess a common structural fragment, a 2,3,4-trihydroxybenzaldehyde moiety connected through hydrazone or hydrazine linker with acylated on N’-nitrogen atom by serine or 4-nitrobenzoic acid fragment. To avoid presence of toxicophoric nitro group in benitrobenrazide molecule we introduced common pharmacophores 4-fluorophenyl or 4-aminophenyl substituents. Modification of benserazide regards an introduction of other endogenous amino acids instead of serine. Herein we report the synthesis of benitrobenrazide and benserazide analogues and preliminary results of inhibitory activity against HK2 evoked by these structural changes. The derivatives contain a fluorine atom or amino group instead of a nitro group in BNB, exhibited the most potent inhibitory effects against HK2 at a concentration of 1 µM, with HK2 inhibition rates of 60% and 54%, respectively.

The protozoan parasite Plasmodium falciparum is the causative pathogen of the most severe form of malaria, for which novel strategies for treatment are urgently required. The primary energy supply for intraerythrocytic stages of Plasmodium is the production of ATP via glycolysis. Due to the parasite’s strong dependence on this pathway and significant structural differences of its glycolytic enzymes compared to their human counterpart, glycolysis is considered as a potential drug target. In this study, we provide the first three-dimensional protein structure of P. falciparum hexokinase (PfHK), containing novel information about the mechanisms of PfHK. We identified for the first time a Plasmodium-specific insertion which lines the active site. Moreover, we propose that this insertion plays a role upon ATP binding. Residues of the insertion further seem to affect the tetrameric interface and therefore suggest a special way of communication among the different monomers. In addition, we confirmed that PfHK is targeted and affected by oxidative posttranslational modifications (oxPTMs). Both Sglutathionylation and Snitrosation revealed an inhibitory effect on the enzymatic activity of PfHK.

Diurnal and seasonal changes of abiotic environmental factors shape plant performance and distribution. Changes of growth temperature and light intensity may vary significantly on a diurnal, but also on a weekly or seasonal scale. Hence, acclimation to a changing temperature and light regime is essential for plant survival and propagation. In the present study, we analyzed photosynthetic CO₂ assimilation and metabolic regulation of the central carbohydrate metabolism in two natural accessions of Arabidopsis thaliana originating from Russia and south Italy during exposure to heat and a combination of heat and high light. Our findings indicate that it is hardly possible to predict photosynthetic capacities to fix CO₂ under combined stress from single stress experiments. Further, capacities of hexose phosphorylation were found to be significantly lower in the Italian than in the Russian accession which could explain an inverted sucrose-to-hexose ratio. Together with the finding of significantly stronger accumulation of anthocyanins under heat/high light these observations indicate a central role of hexokinase activity in stabilization of photosynthetic capacities within a changing environment.