Studies on the stability of ¹²⁵I‐purified porcine zona antigen (PPZA) obtained by chloramine‐T glucose oxidase with lactoperoxidase and N‐bromosuccinimide lodination procedures

Abstract

A purified pig zona antigen (PPZA) was labeled with 125I by chloramine‐T (CL‐T), glucose oxidase with lactoperoxidase (GO‐LP), and N‐bromosuccinimide (N‐BS) iodination procedures. The 125I‐PPZA fractions thus obtained were reconstituted to a concentration of 25,000 dpm/0.1 ml and tested at weekly intervals for binding capacity to a fixed dilution (1:400,000) of PPZA antibody. The 125I‐PPZA obtained by the N‐BS procedure showed greater stability compared to that obtained by CL‐T and GO‐LP methods. The nonspecific binding levels for the N‐BS and GO‐LP methods were comparable and significantly lower than for the CL‐T method.