Human prohormone convertase 4

Claim 1

A method of determining polypeptide prohormone substrates of a human prohormone convertase 4 protein comprising: culturing a cell into which has been introduced an expression vector comprising the following operably linked elements: (a) a transcription promoter; (b) a DNA segment encoding a prohormone convertase polypeptide having an amino acid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Arg) to amino acid number 755 (Thr); and (c) a transcription terminator, wherein the cell expresses a human prohormone convertase protein encoded by the DNA segment and co-expresses a test substrate prohormone polypeptide; and detecting cleavage products resulting from cleavage of the test substrate by the human prohormone convertase 4 protein.

Claim 2

A method of determining polypeptide prohormone substrates of a human prohormone convertase 4 protein comprising: culturing a cell into which has been introduced an expression vector comprising the following operably linked elements: (a) a transcription promoter; (b) a DNA segment encoding a prohormone convertase polypeptide having an amino acid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Arg) to amino acid number 755 (Thr); and (c) a transcription terminator, wherein the cell expresses a human prohormone convertase protein encoded by the DNA segment and co-expresses a test substrate prohormone polypeptide; and detecting cleavage products resulting from cleavage of the test substrate by the human prohormone convertase 4 protein.

Claim 3

A method of determining polypeptide prohormone substrates of a human prohormone convertase 4 protein comprising: combining in vitro with a test substrate polypeptide, an isolated prohormone convertase 4 polypeptide comprising a sequence of amino acid residues selected from the group consisting of: (a) the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 114 (Ser) to amino acid number 443 (Ala); (b) the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 114 (Ser) to amino acid number 755 (Thr); (c) the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Arg) to amino acid number 755 (Thr); and (d) the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 1 (Met) to amino acid number 755 (Thr); and detecting cleavage products resulting from cleavage of the test substrate by the human prohormone convertase 4 protein.

Claim 4

A method of determining polypeptide prohormone substrates of a human prohormone convertase 4 protein comprising: combining in vitro with a test substrate polypeptide, an isolated prohormone convertase 4 polypeptide comprising a sequence of amino acid residues selected from the group consisting of: (a) the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 114 (Ser) to amino acid number 443 (Ala); (b) the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 114 (Ser) to amino acid number 755 (Thr); (c) the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Arg) to amino acid number 755 (Thr); and (d) the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 1 (Met) to amino acid number 755 (Thr); and detecting cleavage products resulting from cleavage of the test substrate by the human prohormone convertase 4 protein.

Claim 5

A method of detecting, in a test sample, the presence of a modulator of human prohormone convertase 4 protein activity, comprising: culturing a cell into which has been introduced an expression vector comprising the following operably linked elements: (a) a transcription promoter; (b) a DNA segment encoding a prohormone convertase polypeptide having an amino acid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Arg) to amino acid number 755 (Thr); and (c) a transcription terminator, wherein the cell expresses the human prohormone convertase protein encoded by the DNA segment and co-expresses a known indicator prohormone polypeptide substrate, in the presence and absence of a test sample; and comparing levels of cleavage products resulting from cleavage of the substrate by the human prohormone convertase, in the presence and absence of the test sample, by a biological or biochemical assay; and determining from the comparison, the presence of the modulator of human prohormone convertase activity in the test sample.

Claim 6

A method of detecting, in a test sample, the presence of a modulator of human prohormone convertase 4 protein activity, comprising: culturing a cell into which has been introduced an expression vector comprising the following operably linked elements: (a) a transcription promoter; (b) a DNA segment encoding a prohormone convertase polypeptide having an amino acid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Arg) to amino acid number 755 (Thr); and (c) a transcription terminator, wherein the cell expresses the human prohormone convertase protein encoded by the DNA segment and co-expresses a known indicator prohormone polypeptide substrate, in the presence and absence of a test sample; and comparing levels of cleavage products resulting from cleavage of the substrate by the human prohormone convertase, in the presence and absence of the test sample, by a biological or biochemical assay; and determining from the comparison, the presence of the modulator of human prohormone convertase activity in the test sample.