A new homogeneous enzyme immunoassay for thyroxine using glycogen phosphorylase b-thyroxine conjugates.

Background: [corrected] Measurement of serum thyroxine (T(4)) concentration is important for diagnosis of thyroid gland diseases. We developed a practical homogeneous enzyme immunoassay for thyroxine analysis in unextracted sera.

Methods: A thyroxine derivative conjugated to a reactive sulfhydryl group of glycogen phosphorylase b (GPb).

Homogeneous enzyme immunoassay for triiodothyronine in serum.

Background: The concentration of triiodothyronine (T3) in human serum is extremely low and can be determined only by very sensitive methods. We developed a homogeneous enzyme immunoassay for T3 analysis in unextracted serum.

Methods: A T(3) derivative was conjugated to the -SH groups of glycogen phosphorylase b (GPb) from rabbit muscle.