title: [Interaction of triiodothyronine-biotin conjugate with binding proteins in immunoassay systems].
abstract: A new construction of a test-system for free thyroid hormone 3,3',5-triiodothyronine determination (free T3) in human blood serum in ELISA and IRMA variants was described. For this purpose a low-molecular weight bifunctional conjugate containing T3 and vitamin H (biotin, Bt) residues was synthesized. The conjugate (T3-Bt) can be bound via its biotin function to biotin-binding proteins on a solid phase whereas its T3-portion can interact with monoclonal antibody against T3 (anti-T3-MAb) labeled with horseradish peroxidase or iodine-125 in an enzyme immunoassay or an immunoradiometric assay system (ELISA or IRMA), respectively. The immunochemical interaction is hindered if the T3 residue takes part as a component of a preformed solid phase complex between T3-Bt and avidin. Computer modeling shows that in this complex glycan component of avidin shields iodothyronine residue. The binding of T3-Bt both with T3-free sites on anti-T3-MAb and the solid phase avidin achieves with help of a delayed T3-Bt addition into avidin-covered containers with preliminary co-incubated labeled anti-T3-MAb and an assayed T3 sample.
authors.forename: M J
authors.initials: MJ
authors.lastname: Navakouskiĭ
authors.forename: I I
authors.initials: II
authors.lastname: Vashkevich
authors.forename: O V
authors.initials: OV
authors.lastname: Sviridov
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology; D001360:Avidin / Q000737:chemistry; D001710:Biotin / Q000737:chemistry*; D002352:Carrier Proteins; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D011487:Protein Conformation; D060327:Solid-Phase Synthesis Techniques; D019809:Streptavidin / Q000737:chemistry / Q000276:immunology; D014284:Triiodothyronine / Q000097:blood* / Q000737:chemistry / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D014284:Triiodothyronine; D001360:Avidin; D001710:Biotin; D019809:Streptavidin