Sheathless CE-MS as a tool for monitoring exchange efficiency and stability of bispecific antibodies

Bispecific monoclonal antibodies (BsAbs) are receiving great attention due to their extensive benefits as biopharmaceuticals and their involvement in IgG4 mediated autoimmune diseases. While the production of BsAbs is getting more accessible, their analytical characterization remains challenging. We explored the potential of sheathless CE-MS for monitoring exchange efficiency and stability of in-house produced bispecific antibodies. Two IgG4 bispecific antibodies with different molecular characteristics were prepared using controlled Fragment antigen binding (Fab)-arm exchange. Separation of BsAbs from their parent monospecific antibodies was achieved using a polyethyleniimine (PEI)-coated capillary and acidic background electrolytes permitting reliable assessment of the exchange efficiency. This was especially valuable for a Fab-glycosylated BsAb where the high glycan heterogeneity resulted in an overlap of masses with the monospecific parent antibody, hindering their discrimination by MS only. The method showed also good capabilities to monitor the stability of the generated BsAbs under different storage conditions. The levels of degradation products were different for the studied antibodies indicating pronounced differences in stability. Overall, the proposed method represents a useful analytical tool for exchange efficiency and stability studies of bispecific antibodies.     

Study of structural and electronic transport properties of Ce-doped LaMnO3

The structural and electronic transport properties of La_1−x Ce _x MnO₃ (x=0.0–1.0) have been studied. All the samples exhibit orthorhombic crystal symmetry and the unit cell volume decreases with Ce doping. They also make a metal-insulator transition (MIT) and transition temperature increases with increase in Ce concentration up to 50% doping. The system La_0.5Ce_0.5MnO₃ also exhibits MIT instead of charge-ordered state as observed in the hole doped systems of the same composition.     

Quantification of ultrasound-induced chain scission in PdII-phosphine coordination polymers

A kinetically inert, reversible coordination polymer (3) was obtained through complexation of dicyclohexylphosphine telechelic poly(tetrahydrofuran) with palladium(II) dichloride. This coordination polymer is unreactive towards palladium(II) dichloride bis(1-diphenylphosphino)dodecane (4), because ligand dissociation in the coordination polymer is slow. However, upon ultrasonication of solutions of 3 in toluene in the presence of 4, formation of palladium(II) heterocomplexes was observed with (31)P NMR spectroscopy. Heterocomplex formation, the consumption of 4, and changes in molecular weight were used to quantify the scission process. In the presence of 60 equivalents of the alkyldiphenylphosphine stopper complex, the reduction in molecular weight was strongly enhanced; over a period of eight hours the weight-averaged molecular weight was reduced from 1.1x10(5) to 2.3x10(4) g mol(-1) while 47 % of the palladium(II) complexes in the coordination polymer had been converted into heterocomplexes. These results show that the system of 3 in combination with scavenger 4 is a suitable system to study the efficiency of ultrasound-induced chain scission of coordination polymers.     

Light‐Driven Enzymatic Decarboxylation of Fatty Acids

The photoenzymatic decarboxylation of fatty acids to alkanes is proposed as an alternative approach for the synthesis of biodiesel. By using a recently discovered photodecarboxylase from Chlorella variabilis NC64A (CvFAP) we demonstrate the irreversible preparation of alkanes from fatty acids and triglycerides. Several fatty acids and their triglycerides are converted by CvFAP in near‐quantitative yield and exclusive selectivity upon illumination with blue light. Very promising turnover numbers of up to 8000 were achieved in this proof‐of‐concept study.     

Two connected inverse spectral transforms

We establish a transformation which connects the potentials of the one-dimensional Dirac and Klein-Gordon operators. This transformation links the solutions of the nonlinear evolution equations solvable by means of the two inverse spectral transforms which use the Dirac and Klein-Gordon direct and inverse spectral problems.