Characterization of the Recombinant Thermostable Lipase (Pf2001) from Pyrococcus furiosus: Effects of Thioredoxin Fusion Tag and Triton X-100

In this work, the lipase from Pyrococcus furiosus encoded by ORF PF2001 was expressed with a fusion protein (thioredoxin) in Escherichia coli. The purified enzymes with the thioredoxin tag (TRX−PF2001Δ60) and without the thioredoxin tag (PF2001Δ60) were characterized, and various influences of Triton X-100 were determined. The optimal temperature for both enzymes was 80°C. Although the thioredoxin presence did not influence the optimum temperature, the TRX−PF2001Δ60 presented specific activity twice lower than the enzyme PF2001Δ60. The enzyme PF2001Δ60 was assayed using MUF-acetate, MUF-heptanoate, and MUF-palmitate. MUF-heptanoate was the preferred substrate of this enzyme. The chelators EDTA and EGTA increased the enzyme activity by 97 and 70%, respectively. The surfactant Triton X-100 reduced the enzyme activity by 50% and lowered the optimum temperature to 60°C. However, the thermostability of the enzyme PF2001Δ60 was enhanced with Triton X-100

Adsorption of BSA (Bovine Serum Albuminum) and lysozyme on poly(vinyl acetate) particles

Abstract Poly(vinyl acetate) (PVAc) particles find many uses in the biomedical field, including the use as particle embolizers. Particularly, embolizing particles can combine physical and chemical effects when they are doped with pharmaceuticals. For this reason, the adsorption of bovine serum albuminum (BSA) and lysozyme (used as model biomolecules) on PVAc particles produced through suspension polymerization is studied in the present manuscript in a broad range of pH values. It is shown that significant amounts of BSA and lysozyme can be adsorbed onto PVAc particles in the vicinities of the isoelectric point of the biomolecules (0.65mg of BSA and 1.0mg of lysozyme per g of PVAc), allowing for production of chemoembolizers through adsorption. Particularly, it is shown that lysozyme still presents residual activity after the adsorption process, which can constitute very important characteristic for real biomedical applications

Immobilization of myoglobin in sodium alginate composite membranes

<title>Abstract</title><p>The immobilization of myoglobin in sodium alginate films was investigated with the aim of evaluating the protein stability in an ionic polymeric matrix. Myoglobin was chosen due to the resemblance to each hemoglobin tetramer. Sodium alginate, being a natural polysaccharide, was selected as the polymeric matrix because of its chemical structure and film-forming ability. To improve the mechanical resistance of sodium alginate films, the polymer was deposited over the surface of a cellulose acetate support by means of ultrafiltration. The ionic crosslink of sodium alginate was investigated by calcium ions. Composite membrane characterization comprised water swelling tests, water flux, SEM images and UV-visible spectroscopy. The electrostatic interaction between the protein and the polysaccharide did not damage the UV-visible pattern of native myoglobin. A good affinity between sodium alginate and cellulose acetate was observed. The top layer of the dense composite membrane successfully immobilized Myoglobin, retaining the native UV-visible pattern for two months.</p