# US 5,702,910 A · Method of sandwich immunoassay for N-peptide > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,702,910 A - Document ID: US5702910A - Status: Granted - Kind: A - Application number: 08/569,461 - Filed: 1995-12-08 - Granted: 1997-12-30 - Earliest claimed: 1994-12-09 - Assignees: Shionogi & Co., Ltd. - Inventors: Yoshito Numata; Hidehisa Asada; Keiji Dohi; Takahiro Fukunaga; Yasushi Taniguchi - Web page: https://patentgrep.com/patent/US5702910A ## CPC - G01N 33/6893: {related to diseases not provided for elsewhere} - C07K 16/26: against hormones {; against hormone releasing or inhibiting factors} - G01N 2333/58: Atrial natriuretic factor complex; Atriopeptin; Atrial natriuretic peptide [ANP]; Brain natriuretic peptide [BNP, proBNP]; Cardionatrin; Cardiodilatin - G01N 2474/20: Immunohistochemistry assay - Y10S 436/808: Automated or kit - Y10S 436/811: Test for named disease, body condition or organ function - Y10S 530/808: Materials and products related to genetic engineering or hybrid or fused cell technology, e.g. hybridoma, monoclonal products - Y10S 530/809: Fused cells, e.g. hybridoma - Y10S 530/829: Blood - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - C07K: PEPTIDES (peptides in foodstuffs A23; obtaining protein compositions for foodstuffs, working-up proteins for foodstuffs A23J; preparations for medicinal purposes A61K; peptides containing beta-lactam rings C07D; cyclic dipeptides not having in their molecule any other peptide link than those which form their ring, e.g. piperazine-2,5-diones, C07D; ergot alkaloids of the cyclic peptide type C07D519/02; macromolecular compounds having statistically distributed amino acid units in their molecules, i.e. when the preparation does not provide for a specific; but for a random sequence of the amino acid units, homopolyamides and block copolyamides derived from amino acids C08G69/00; macromolecular products derived from proteins C08H1/00; preparation of glue or gelatine C09H; single cell proteins, enzymes C12N; genetic engineering processes for obtaining peptides C12N15/00; compositions for measuring or testing processes involving enzymes C12Q; investigation or analysis of biological material G01N33/00) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract The present invention relates to a sandwich immunoassay for rapidly and readily measuring N-peptide using two kinds of monoclonal antibodies recognizing different portions of the N-peptide. The method for measuring N-peptide or a precursor thereof includes the steps of: incubating a mixture containing a sample and a first monoclonal antibody recognizing a portion of N-peptide; adding a labelled second monoclonal antibody recognizing a portion of N-peptide to the mixture, followed by further incubation; and detecting the resulting antigen-antibody complex in the mixture. Alternatively, the method includes the steps of: incubating a mixture containing a sample, a first monoclonal antibody recognizing a portion of N-peptide, and a labelled second monoclonal antibody recognizing another portion of N-peptide; and detecting the resulting antigen-antibody complex. ## Claims ### Claim 1 A method for measuring .gamma.-hANP(1-98) or a precursor thereof, comprising the steps of: incubating a mixture containing a sample and a first monoclonal antibody which specifically binds the .gamma.-hANP(1-98); adding a labeled second monoclonal antibody which specifically binds the .gamma.-hANP(1-98) to the mixture, followed by further incubation; detecting a resulting antigen-antibody complex in the mixture; and correlating the detected antigen-antibody complex with an amount of the .gamma.-hANP(1-98), wherein the first or second monoclonal antibody binds a portion of an amino acid sequence from the 43 position to the 67 position of the .gamma.-hANP(1-98). ### Claim 2 A method for measuring .gamma.-hANP(1-98) or a precursor thereof, comprising the steps of: incubating a mixture containing a sample, a first monoclonal antibody which specifically binds the .gamma.-hANP(1-98), and a labeled second monoclonal antibody which specifically binds the .gamma.-hANP(1-98); detecting a resulting antigen-antibody complex in the mixture; and correlating the detected antigen-antibody complex with an amount of the .gamma.-hANP(1-98), wherein the first or second monoclonal antibody binds a portion of an amino acid sequence from the 43 position to the 67 position of the .gamma.-hANP(1-98). ### Claim 3 (depends on 1, 2) A method according to claim 1 or 2, wherein the first or second monoclonal antibody is 7B6. ### Claim 4 (depends on 3) A method according to claim 3, wherein one of the first and second monoclonal antibodies is 7B6, and the other is a monoclonal antibody that binds a portion of the amino acid sequence of the .gamma.-hANP(1-98), of which a binding site is different from that of the 7B6. ### Claim 5 (depends on 1, 2) A method according to claim 1 or 2, wherein one of the first and second monoclonal antibodies specifically binds a portion of the amino acid sequence from the 43 position to the 67 position of the .gamma.-hANP(1-98), and the other monoclonal antibody specifically binds a portion of the amino acid sequence from the 1 position to the 25 position of the .gamma.-hANP(1-98). ### Claim 6 (depends on 5) A method according to claim 5, wherein the other monoclonal antibody is KY-ANP-III. ### Claim 7 (depends on 5) A method according to claim 5, wherein the first monoclonal antibody specifically binds a portion of the amino acid sequence from the 1 position to the 25 position of the .gamma.-hANP(1-98), and the second monoclonal antibody specifically binds a portion of the amino acid sequence from the 43 position to the 67 position of the .gamma.-hANP(1-98). ### Claim 8 (depends on 7) A method according to claim 7, wherein the first monoclonal antibody is KY-ANP-III, and the second monoclonal antibody is 7B6. ### Claim 9 (depends on 1, 2) A method according to claim 1 or 2, wherein the second monoclonal antibody is labeled with at least one selected from the group consisting of a radioisotope, an enzyme, a colloidal gold, a fluorescent substance, and a luminescent substance. ### Claim 10 (depends on 9) A method according to claim 9, wherein the second monoclonal antibody is labelled with a radioisotope or an enzyme.