Mediating trade-off between activity and selectivity in alkynes semi-hydrogenation via a hydrophilic polar layer.

As a crucial industrial process for the production of bulk and fine chemicals, semi-hydrogenation of alkynes faces the trade-off between activity and selectivity due to undesirable over-hydrogenation. By breaking the energy linear scaling relationships, we report an efficient additive-free WO3-based single-atom Pd catalytic system with a vertical size effect of hydrogen spillover. Hydrogen spillover induced hydrophilic polar layer (HPL) with limited thickness on WO3-based support exhibits unconventional size effect to Pd site, in which over-hydrogenation is greatly suppressed on Pd1 site due to the polar repulsive interaction between HPL and nonpolar C=C bonds, whereas this is invalid for Pd nanoparticles with higher altitudes. By further enhancing the HPL through Mo doping, activated Pd1/MoWO3 achieves recorded performance of 98.4% selectivity and 10200 h-1 activity for semi-hydrogenation of 2-methyl-3-butyn-2-ol, 26-fold increase in activity of Lindlar catalyst. This observed vertical size effect of hydrogen spillover offers broad potential in catalytic performance regulation.

Purification and Characterization of a Novel Fibrinolytic Enzyme from Cipangopaludina Cahayensis.

BACKGROUND: Cipangopaludina cahayensis contains active fibrinolytic proteins and has been considered a potential anti-cancer agent. However, its anti-cancer characteristics and functions have yet to be elucidated. OBJECTIVES: To study the fibrinolytic activity and anticancer activity of crude protein extracts from Cipangopaludina cahayensis. MATERIALS AND METHODS: Crude proteases were separated and extracted from the Cipangopaludina cahayensis through homogenization, desalting, ammonium sulfate fractionation, dialysis, and ion exchange chromatography. The fibrinolytic activity of extracted proteins was assessed using the fiber plate method. Total protein concentrations of the crude proteases were determined via BCA assay. Molecular weights (MWs) were determined through SDS-PAGE electrophoresis. RESULTS: The crude extract had a MW of ~ 50 kDa, and the highest protein concentration was 3.026 mg.mL-1. The optimum pH for fibrinolytic activity was 7.0. Cell culture assays demonstrated that the addition of the crude enzyme extracts to the human ovary cancer cell line Ovcar-3 resulted in significant growth defects. CONCLUSIONS: Our data showed that crude proteins purified from Cipangopaludina cahayensis are novel fibrinolytic proteases and have potential anti-cancer propertie.