The preparation of puromycin antibody and its use in enzyme immunoassay for the quantification using beta-D-galactosidase as a label.

An antibody specific for puromycin (PU) was prepared by immunization of rabbits with a PU conjugate of bovine serum albumin, which was newly synthesized by coupling PU to mercaptosuccinylated bovine serum albumin via a cross-linker, N-(gamma-maleimidobutyryloxy)succinimide. Enzyme labeling of PU was performed using beta-D-galactosidase [EC 3.2.1.23] via N-(m-maleimidobenzoyloxy) succinimide. An ultrasensitive and specific enzyme immunoassay for PU was developed utilizing these reagents by a double antibody technique. The standard curve of the assay was linear in the range of 2 pg to 100 pg, and the lower limit of detection was 28.2 pm (2 pg/tube); so the enzyme immunoassay was found to be approximately 326,000 times more sensitive than a microbiological assay. Further, the enzyme immunoassay is free from interference by any purine or pyrimidine analogs, or by other drugs commonly used for the inhibition of protein synthesis. Using this assay, drug levels were easily determined in rat tissue following PU administration. Since PU is extensively available as an inhibitor of protein synthesis, the enzyme immunoassay should provide useful tool for developing biochemical and toxicity studies of PU.