Highly sensitive immunoassays for three forms of rat brain enolase

Highly sensitive enzyme immunoassay systems for three forms (alpha alpha, alpha gamma, and gamma gamma) of rat brain enolase were prepared by use of specific antisera to two distinct subunits (alpha and gamma) of the isozymes and beta-D-galactosidase from Escherichia coli as label. Less than fmol-levels of the homologous dimer forms (alpha alpha and gamma gamma) could be determined with the corresponding antibody F(ab')2-bound solid-phase and the antibody Fab'-beta-D-galactosidase complex. The hybrid form (alpha gamma) could also be assayed specifically by use of the antibody to one subunit as solid-phase, and the antibody to another subunit as labelled complex with a minimum detectable sensitivity of 1 fmol.