Search

In the present study, arsanical-based affinity chromatography for pyruvate kinase (PK) isolation was explored. p -Arsanilic acid (4-aminophenyl arsonic acid), which contains an arsonic acid moiety structurally similar to inorganic pentavalent arsenate, was conjugated to Sepharose 4B via its para -amino group to form an As(V)–Sepharose matrix. The cellular proteins from KB cells bound to arsonic acid moieties were eluted by 50 m M sodium arsenate in Tris–HCl buffer (50 m M , pH 7.6). A single protein band with a molecular mass of 58 kDa was shown on a sodium dodecyl sulfate–polyacrylamide gel. By immunoblotting, amino acid sequencing and enzymatic analysis, the sodium arsenate-eluted 58-kDa protein was demonstrated to be a human PK (type M2). By using this one-step As(V)–Sepharose chromatography, PK from KB cells was purified 35.4-fold with a specific activity of 153.15 U/mg protein in the presence of 6 m M fructose-1,6-biphosphate. Although PK was eluted from an As(V)–Sepharose column with sodium arsenate, PK activity was apparently inhibited by the used eluent system, but not by p -arsanilic acid, indicating a specific interaction of As(V) to PK. In summary, our results indicate that As(V)–Sepharose can serve as a simple and efficient chromatographic support for PK purification from KB cells.

Biomimetic nanostructures have shown to enhance the optical absorption of Ga(0.5)In(0.5)P/GaAs/Ge triple junction solar cells due to excellent antireflective (AR) properties that, however, are highly dependent on their geometric dimensions. In practice, it is challenging to control fabrication conditions which produce nanostructures in ideal periodic arrangements and with tapered side-wall profiles, leading to sacrificed AR properties and solar cell performance. In this work, we introduce compound biomimetic nanostructures created by depositing a layer of silicon dioxide (SiO(2)) on top of titanium dioxide (TiO(2)) nanostructures for triple junction solar cells. The device exhibits photogenerated current and power conversion efficiency that are enhanced by ~8.9% and ~6.4%, respectively, after deposition due to their improved antireflection characteristics. We further investigate and verify the optical properties of compound structures via a rigorous coupled wave analysis model. The additional SiO(2) layer not only improves the geometric profile, but also serves as a double-layer dielectric coating. It is concluded that the compound biomimetic nanostructures exhibit superior AR properties that are relatively insensitive to fabrication constraints. Therefore, the compound approach can be widely adopted for versatile optoelectronic devices and applications.