Enzyme immunoassay of prostaglandin F2alpha

An enzyme immunoassay for prostaglandin F2alpha was developed in which the hapten molecule was labeled with alkaline phosphatase protein. After competition between the enzyme-labeled prostaglandin F2alpha and the free prostaglandin F2alpha in their immunoreaction with prostaglandin F2alpha-specific antiserum, the antigen-antibody conjugate was precipitated by the double antibody method, and the activity of precipitated alkaline phosphatase was determined. Calibration curves of enzyme activity versus the amount of added prostaglandin F2alpha were constructed. Under optimal conditions of pH, buffer concentration, incubation time and amount of antibody and enzyme-labeled antigen, prostaglandin F2alpha could be measured quantitatively in the range of 0.5 pmol to 1 nmol. This method was applied for the determinations of prostaglandin F2alpha added to urine.