Bioluminescent enzyme immunoassay for pituitary adenylate cyclase activating polypeptide 38 (PACAP38) Original Research Article

Pituitary adenylate cyclase activating polypeptide 38 (PACAP38) is a novel peptide hormone and has a variety of biological actions. In studies of the physiological behavior of endogenous PACAP, the determination of PACAP38 levels in biological materials requires a highly sensitive and specific method. Therefore, we developed a sensitive bioluminescent enzyme immunoassay (BL-EIA) for PACAP38 using acetate kinase (AK) as a reporter enzyme and the luciferin–luciferase reaction. Accordingly, we developed BL-EIA using biotinylated PACAP38 as a labeled antigen and biotinylated AK–streptavidin complex as a detector of biotin on solid phase. The measurable range was 62–16000 pg ml−1 for PACAP38 by the proposed BL-EIA. The PACAP38 concentration of various tissue extracts of rat and plasma of rat and human could be measured by the proposed BL-EIA. Furthermore, a high degree of correlation for various samples was found between the results obtained by BL-EIA and radioimmunoassay.