An enzyme immunoassay for K-76 monocarboxylic acid, a novel anticomplementary compound

A competitive enzyme immunoassay for K-76 monocarboxylic acid (K-76COOH), a novel anticomplementary compound, was developed. K-76COOH was directly coupled with bovine serum albumin through a formation of Schiff base and successive reduction. The spectral data of the conjugate showed no evidence of a Schiff base form. Using the specific antiserum, the proposed homologous assay made it possible to detect K-76COOH at the lowest value of 1 ng/ml of plasma. The immunoassay was validated by the correlation with HPLC analyses. The time courses of plasma levels of K-76COOH after a single oral administration to beagle dogs were precisely determined with a very low absorption efficiency. From these results, it is suggested that the plasma values obtained are insufficient for K-76COOH to exert its anticomplementary action in vivo; thus K-76COOH may have another immunopharmacological function.