The N-glycan moiety of IgG-Fc has a significant impact on multifaceted properties of antibodies such as in their effector function, structure, and stability. Numerous studies have been devoted to understanding its biological effect since the exact composition of the Fc N-glycan modulates the magnitude of effector functions such as the antibody-dependent cell mediated cytotoxicity (ADCC), and the complement-dependent cytotoxicity (CDC). To date, systematic analyses of the properties and influence of glycan variants have been of great interest. Understanding the principles on how N-glycosylation modulates those properties is important for the molecular design, manufacturing, process optimization, and quality control of therapeutic antibodies. In this study, we have separated a model therapeutic antibody into three fractions according to the composition of the N-glycan by using a novel FcγRIIIa chromatography column. Notably, Fc galactosylation was a major factor influencing the affinity of IgG-Fc to the FcγRIIIa immobilized on the column. Each antibody fraction was employed for structural, biological, and physicochemical analysis, illustrating the mechanism by which galactose modulates the affinity to FcγRIIIa. In addition, we discuss the benefits of the FcγRIIIa chromatography column to assess the heterogeneity of the N-glycan.

In the photocatalytic conversion of CO2 using H2O as the electron donor, there are four candidates of the intermediate species in the solution: hydrated CO2 molecule (CO2(aq)), carbonic acid (H2CO3), bicarbonate (HCO3 –), and carbonate (CO3 2–) ions. The concentrations of all four species in the system at equilibrium can be controlled by controlling the temperature, pH value, and concentration of the countercation. According to our experiments conducted under different conditions, we narrowed the possible intermediates down to two: CO2(aq) and HCO3 –. The isotopic experiment using 13CO2 and in situ infrared spectroscopy revealed that CO2(aq) reacts with the hydroxyl group anchored on the Ga atom on the surface of ZnGa2O4/Ga2O3 to form bidentate HCO3–Ga, followed by the formation of bidentate HCOO–Ga via monodentate HCO3–Ga. We conclude that bidentate HCOO–Ga is the real intermediate species for the photocatalytic conversion of CO2 by H2O as the electron donor over Ag/ZnGa2O4/Ga2O3 catalyst, and it decomposes into CO as a product.

The introduction of two mutations (G74C/C188S) based on the estimated reaction mechanism resulted in the inversion of enantioselectivity of arylmalonate decarboxylase, which catalyses the asymmetric decarboxylation of arylmethylmalonate to give optically active arylpropionate.

The introduction of only one mutation based on the estimated reaction mechanism endowed arylmalonate decarboxylase with a racemase activity, which catalyses racemisation of alpha-arylpropionates.