Abstract: The present invention provides a method for inexpensively, easily and efficiently modifying the C-terminus of a protein or peptide; a method for easily and reliably isolating a C-terminal peptide fragment of a protein or peptide; and a method for rapidly, accurately and reliably determining an amino acid sequence of a protein or peptide by using a mass spectroscope. A method comprising the step of adding a formylation reagent and a catalyst to a protein or peptide to convert a carboxyl group into an aldehyde group. A method comprising the step of reacting a nucleophilic reagent with the aldehyde group to modify the C-terminus of the protein or peptide. A method comprising the step of reacting a support having a nucleophilic group to immobilize the protein or peptide. A method comprising the step of fragmenting the immobilized protein or peptide, washing the support, and isolating the C-terminal peptide fragment from the support.

Abstract: The present invention provides a method for specifically recovering a C-terminal peptide fragment, and a method for easily determining the sequence of a C-terminal peptide fragment, which is difficult to be determined by a conventional method, with the use of a mass spectrometer, in particular a method capable of de novo sequencing of a C-terminal peptide fragment. A method for selectively recovering a C-terminal peptide of a protein, comprising the steps of: in a cleavage product of a protein containing a C-terminal peptide fragment (A) having an ?-amino group but not having an ?-amino group and the other peptide fragments (B) having an ?-amino group and an ?-amino group, selectively modifying the ?-amino groups to obtain a C-terminal peptide fragment modified (A?) and the other peptide fragments modified (B?); and separating the C-terminal peptide fragment modified (A?) from the modified cleavage product by allowing a carrier to hold the other peptide fragments modified (B?) via the ?-amino group.

Abstract: There are provided hyperthermostable proteases having an amino acid sequences represented by SEQ ID Nos. 1, 3 and 5 of the Sequence Listing or functional equivalents thereof and hyperthermostable protease genes encoding those hyperthermostable protease. There is also disclosed a process for preparation of a hyperthermostable protease by culturing a transformant containing the gene.

Abstract: There are provided hyperthermostable proteases having an amino acid sequences represented by SEQ ID Nos. 1, 3 and 5 of the Sequence Listing or functional equivalents thereof and hyperthermostable protease genes encoding those hyperthermostable protease. There is also disclosed a process for preparation of a hyperthermostable protease by culturing a transformant containing the gene.

Abstract: There are provided hyperthermostable proteases having an amino acid sequences represented by SEQ ID NOs: 1, 3 and 5 of the Sequence Listing or functional equivalents thereof and hyperthermostable protease genes encoding those hyperthermostable protease. There is also disclosed a process for preparation of a hyperthermostable protease by culturing a transformant containing the gene.

Abstract: There are provided hyperthermostable proteases having an amino acid sequences represented by SEQ ID Nos. 1, 3 and 5 of the Sequence Listing or functional equivalents thereof and hyperthermostable protease genes encoding those hyperthermostable protease. There is also disclosed a process for preparation of a hyperthermostable protease by culturing a transformant containing the gene.

Abstract: A method for performing site-directed mutagenesis characterized in that the method includes the step of carrying out PCR by the use of a double-stranded DNA vector having one or more amber codons, the vector resulting from insertion of a target DNA fragment for site-directed mutagenesis, and at least two kinds of selection primers; and a kit for site-directed mutagenesis for use in the above method, characterized in that the kit includes amber codon reversion primers. According to the present invention, there can be provided a method for performing site-directed mutagenesis and a kit, which is useful for genetic engineering or protein engineering, more simply and rapidly. By using the method and the kit of the present invention, it is possible to efficiently obtain a mutation-introduced gene at the desired position by simply transforming a host with a PCR product obtained by PCR.

Abstract: A method for performing site-directed mutagenesis characterized in that the method includes the step of carrying out PCR by the use of a double-stranded DNA vector having one or more amber codons, the vector resulting from insertion of a target DNA fragment for site-directed mutagenesis, and at least two kinds of selection primers; and a kit for site-directed mutagenesis for use in the above method, characterized in that the kit includes amber codon reversion primers. According to the present invention, there can be provided a method for performing site-directed mutagenesis and a kit, which is useful for genetic engineering or protein engineering, more simply and rapidly. By using the method and the kit of the present invention, it is possible to efficiently obtain a mutation-introduced gene at the desired position by simply transforming a host with a PCR product obtained by PCR.

Abstract: There are provided hyperthermostable proteases having an amino acid sequences represented by SEQ ID NOs: 1, 3 and 5 of the Sequence Listing or functional equivalents thereof and hyperthermostable protease genes encoding those hyperthermostable protease. There is also disclosed a process for preparation of a hyperthermostable protease by culturing a transformant containing the gene.

Abstract: There are provided hyperthermostable proteases having an amino acid sequences represented by SEQ ID Nos. 1, 3 and 5 of the Sequence Listing or functional equivalents thereof and hyperthermostable protease genes encoding those hyperthermostable protease. There is also disclosed a process for preparation of a hyperthermostable protease by culturing a transformant containing the gene.

Abstract: To provide an amino terminal protecting group-releasing enzyme characterized in that the enzyme possesses an activity for releasing a protecting group by acting on a peptide of which amino terminal is blocked by the protecting group, and exhibits the activity for two or more protecting groups, or a functional equivalent thereof; a DNA encoding the same; a method for producing the enzyme; a method for removing amino terminal protecting group including the step of subjecting to a reaction with the enzyme to release amino terminal protecting group; and a method for analyzing an amino acid sequence. The above enzyme is useful in the analysis of an amino acid sequence of peptides, particularly proteins and peptides, of which amino terminal is blocked by unknown protecting groups.

Abstract: There is disclosed a hyperthermostable protease gene originating in Pyrococcus furiosus, in particular, a hyperthermostable protease gene encoding the amino acid sequence represented by the SEQ ID NO 1 in the Sequence Listing or a part thereof which retains the activity of the hyperthermostable protease. There is also disclosed a process for producing the protease by culturing a transformant transformed with a plasmid into which the above gene has been inserted.