Development of a Highly Active Fluorescence-Based Detector for Yeast G Protein-Coupled Receptor Ste2p.

Twenty analogs of [Orn,D-Ala]α-factor were synthesized and assayed for their biological activities: seven analogs of [Orn,X]α-factor, seven analogs of [X,D-Ala]α-factor, five analogs of [X,X,D-Ala]α-factor, and native α-factor (X = amino acids). Their biological activities (halo, gene induction, and affinity) were measured using Y7925 and LM102 and compared with those of native α-factor (100%). G protein-coupled receptor was expressed in strain LM102 containing pESC-LEU- vector.

Deracemization of unnatural amino acid: homoalanine using D-amino acid oxidase and ω-transaminase.

A deracemization method was developed to generate optically pure L-homoalanine from racemic homoalanine using D-amino acid oxidase and ω-transaminase. A whole cell reaction using a biphasic system converted 500 mM racemic homoalanine to 485 mM L-homoalanine (>99% ee).

Kinetic resolution of 3-fluoroalanine using a fusion protein of D-amino acid oxidase with Vitroscilla hemoglobin.

In this study, a fusion protein (VHb-DAAO) of D-amino acid oxidase (DAAO) with Vitreoscilla hemoglobin (VHb) was functionally expressed in Escherichia coli and purified. The k(cat) value VHb-DAAO (47.1 s⁻¹) towards rac-3-flouroalanine was about 2-fold higher than that of DAAO (21.

Recombinant S-layer proteins of Lactobacillus brevis mediating antibody adhesion to calf intestine alleviated neonatal diarrhea syndrome.

A chimeric gene encoding enhanced green fluorescent protein (EGFP) and a S-layer protein from Lactobacillus brevis KCTC3102, and/or two copies of the Fc-binding Z-domain, a synthetic analog of the B-domain of protein A, was constructed and expressed in Escherichia coli BL21(DE3). The S-layer fusion proteins produced in a 500-l fermentor were likely to be stable in the range of pH 5 to 8 and 0 degree to 40 degrees . Their adhesive property enabled an easy and rapid immobilization of enzymes or antibodies on solid materials such as plastics, glass, sol-gel films, and intestinal epithelial cells.

Catalytic properties of the PepQ prolidase from Escherichia coli.

The PepQ prolidase from Escherichia coli catalyzes the hydrolysis of dipeptide substrates with a proline residue at the C-terminus. The pepQ gene has been cloned, overexpressed, and the enzyme purified to homogeneity. The k(cat) and k(cat)/K(m) values for the hydrolysis of Met-Pro are 109 s(-1) and 8.

Fusion protein of Vitreoscilla hemoglobin with D-amino acid oxidase enhances activity and stability of biocatalyst in the bioconversion process of cephalosporin C.

In this study we constructed an artificial flavohemoprotein by fusing Vitreoscilla hemoglobin (VHb) with D-amino acid oxidase (DAO) of Rhodotorula gracilis to determine whether bacterial hemoglobin can be used as an oxygen donor to immobilized flavoenzyme. This chimeric enzyme significantly enhanced DAO activity and stability in the bioconversion process of cephalosporin C. In a 200-mL bioreactor, the catalytic efficiency of immobilized VHb-DAO against cephalosporin C was 12.