Abstract: The screening method of the present invention is useful for screening drugs such as insulin secretagogues having an insulin secretagogue activity with minimized side effects (hypoglycemia induction, etc.). The transformant in which a polynucleotide encoding the fusion protein used for the screening method is introduced, the screening kit comprising the transformant, etc. are also useful for screening excellent drugs.

Abstract: Secreted luciferases which are different from those known heretofore have been desired. The present invention provides a luciferase mutant comprising an amino acid sequence in which at least one amino acid selected from amino acids at the positions of 1 to 4 is deleted in the amino acid sequence of SEQ ID NO: 2.

Abstract: A target protein is prepared as soluble protein using a recombinant protein expression system. An expression vector is used that includes (1) an expression-inducible promoter sequence; (2) a first coding sequence including a polynucleotide coding for a polypeptide that is represented by the formula (Z)n; and (3) a second coding sequence that includes a polynucleotide that codes for a target protein. A method of producing the target protein is also used that includes expressing protein using this expression vector.

Abstract: Methods for extending light-emitting time of a solution of a calcium-binding photoprotein that instantaneously emits light by binding to calcium ions are provided. In the light-emitting reaction system of a solution of a calcium-binding photoprotein, a light-emitting reaction is performed in the presence of an anion capable of binding to the calcium ion or the cation that can be substituted for the calcium ion and/or a cation that can bind to the calcium-binding site of the calcium-binding photoprotein with a lower affinity than the calcium ion or the cation that can be substituted for the calcium ion without activating the calcium-binding photoprotein.

Abstract: There has been a need for coelenterazine analogs that exhibit luminescence properties different from those of known coelenterazine analogs. The present invention provides the compound represented by general formula (1).

Abstract: Coelenterazine analogs having luminescence properties different from those of known coelenterazine analogs are desired for various luciferases. The invention provides compounds represented by general formula (1) below.

Abstract: Secreted luciferases which are different from those known heretofore have been desired. The present invention provides a luciferase mutant comprising an amino acid sequence in which at least one amino acid selected from amino acids at the positions of 1 to 4 is deleted in the amino acid sequence of SEQ ID NO: 2.

Abstract: Secreted luciferases which are different from those known heretofore have been desired. The present invention provides a luciferase mutant comprising an amino acid sequence in which at least one amino acid selected from amino acids at the positions of 1 to 4 is deleted in the amino acid sequence of SEQ ID NO: 2.

Abstract: Coelenterazine analogs having luminescence properties different from those of known coelenterazine analogs are desired for various luciferases. The invention provides compounds represented by general formula (1) below.

Abstract: There has been a demand for a codon-optimized gene for the mutated catalytic domain of Oplophorus luciferase, which is capable of efficiently expressing a protein both in a cultured animal cell and Escherichia coli. There has also been a demand for a substrate coelenterazine analogue showing a higher activity than that of native 19 kDa protein. The invention provides a polynucleotide comprising a polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2. According to the invention, bis-coelenterazine is used as a substrate coelenterazine analogue suitable for the photoprotein encoded by the polynucleotide comprising the polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2.

Abstract: Secreted luciferases which are different from those known heretofore have been desired. The present invention provides a luciferase mutant comprising an amino acid sequence in which at least one amino acid selected from amino acids at the positions of 1 to 4 is deleted in the amino acid sequence of SEQ ID NO: 2.

Abstract: There has been a demand for a codon-optimized gene for the mutated catalytic domain of Oplophorus luciferase, which is capable of efficiently expressing a protein both in a cultured animal cell and Escherichia coli. There has also been a demand for a substrate coelenterazine analog showing a higher activity than that of native 19 kDa protein. The invention provides a polynucleotide comprising a polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2. According to the invention, bis-coelenterazine is used as a substrate coelenterazine analog suitable for the photoprotein encoded by the polynucleotide comprising the polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2.

Abstract: Secreted luciferases which are different from those known heretofore have been desired. The present invention provides a luciferase mutant comprising an amino acid sequence in which at least one amino acid selected from amino acids at the positions of 1 to 4 is deleted in the amino acid sequence of SEQ ID NO: 2.

Abstract: There has been a demand for a codon-optimized gene for the mutated catalytic domain of Oplophorus luciferase, which is capable of efficiently expressing a protein both in a cultured animal cell and Escherichia coli. There has also been a demand for a substrate coelenterazine analogue showing a higher activity than that of native 19 kDa protein. The invention provides a polynucleotide comprising a polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2. According to the invention, bis-coelenterazine is used as a substrate coelenterazine analogue suitable for the photoprotein encoded by the polynucleotide comprising the polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2.

Abstract: Secreted luciferases which are different from those known heretofore have been desired. The present invention provides a luciferase mutant comprising an amino acid sequence in which at least one amino acid selected from amino acids at the positions of 1 to 4 is deleted in the amino acid sequence of SEQ ID NO: 2.

Abstract: There has been a demand for a codon-optimized gene for the mutated catalytic domain of Oplophorus luciferase, which is capable of efficiently expressing a protein both in a cultured animal cell and Escherichia coli. There has also been a demand for a substrate coelenterazine analog showing a higher activity than that of native 19 kDa protein. The invention provides a polynucleotide comprising a polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2. According to the invention, bis-coelenterazine is used as a substrate coelenterazine analog suitable for the photoprotein encoded by the polynucleotide comprising the polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2.

Abstract: Secreted luciferases which are different from those known heretofore have been desired. The present invention provides a luciferase mutant comprising an amino acid sequence in which at least one amino acid selected from amino acids at the positions of 1 to 4 is deleted in the amino acid sequence of SEQ ID NO: 2.

Abstract: There has been a demand for a codon-optimized gene for the mutated catalytic domain of Oplophorus luciferase, which is capable of efficiently expressing a protein both in a cultured animal cell and Escherichia coli. There has also been a demand for a substrate coelenterazine analogue showing a higher activity than that of native 19 kDa protein. The invention provides a polynucleotide comprising a polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2. According to the invention, bis-coelenterazine is used as a substrate coelenterazine analogue suitable for the photoprotein encoded by the polynucleotide comprising the polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2.

Abstract: Described include (1) a substituted pyrazine compound of general formula (VIII): and (2) a process for producing the substituted pyrazine compound of general formula (VIII), where R1 is hydrogen, a halogen, a substituted or unsubstituted hydrocarbon group, or a substituted or unsubstituted heterocyclic group, and R4 is a protecting group. The process comprises (1) the step of reacting 2-amino-3,5-dibromo-6-chloropyrazine with R1MgX and ZnCl2 in the presence of a palladium catalyst to produce a compound of general formula (V); (2) the step of reacting the compound of general formula (V) with a compound of general formula (VI) to produce a compound of general formula (VII); and (3) the step of reacting the compound of formula (VII) with tributyl(vinyl)tin in the presence or a palladium catalyst to given the compound of general formula (VIII).

Abstract: There has been a demand for a codon-optimized gene for the mutated catalytic domain of Oplophorus luciferase, which is capable of efficiently expressing a protein both in a cultured animal cell and Escherichia coli. There has also been a demand for a substrate coelenterazine analogue showing a higher activity than that of native 19 kDa protein. The invention provides a polynucleotide comprising a polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2. According to the invention, bis-coelenterazine is used as a substrate coelenterazine analogue suitable for the photoprotein encoded by the polynucleotide comprising the polynucleotide consisting of the nucleotide sequence of SEQ ID NO: 2.