Patent ID: 7659078

Claim:
A method of determining amount of prostaglandin in a plasma sample comprising: (1) providing a plasma sample from a patient in contact with a surface coated with an anti-immunoglobulin antibody; (2) incubating the plasma sample with an effective amount of an anti-6-keto-prostaglandin F 1α (6-keto-PGF 1α ) antibody, wherein the anti-immunoglobulin antibody binds to the anti-6-keto-PGF 1α -antibody, and with a conjugate comprising 6-keto-PGF 1α covalently bound to an aequorin mutant, wherein said aequorin mutant comprises serine substitutions for all three cysteine residues as present in wild-type aequorin (Cys→Ser), wherein said aequorin mutant further comprises a single cysteine residue substituted at amino acid position 69 (Ala69 →Cys), 70 (Gly70 →Cys), 74 (Gly74 →Cys) or 76 (Glu76 →Cys), and wherein the 6-keto-PGF 1α is coupled to the aequorin mutant via reaction with the sulfhydryl group of the single cysteine; (3) removing any unbound anti-6-keto-PGF 1α -antibody and said conjugate following incubation; (4) measuring light intensity of the 6-keto-PGF 1α conjugate bound to the anti-immunoglobulin antibody; and (5) correlating the light intensity of the bound 6-keto-PGF 1α conjugate with the amount of the prostaglandin in the plasma sample.