Syva Company

Syntex (u.s.a.) Inc.

Robert A Yoshida

Edward T Maggio

Joel E Lavine

Jean Kam

Conjugates of heavy atoms containing analytes or their analogs and fluorescent molecules are covalently bonded to macromolecular supports to minimize the interference of fluorescence during assays, due to non-specific binding of serum proteins to the conjugate.

Method for competitive protein binding assays inhibiting non-specific

Compositions for competitive protein binding assays inhibiting

An improved method is provided for performing an enzyme immunoassay, where the signal producing compound is chemically labile. Particularly, in homogeneous enzyme immunoassays, where the enzyme is conjugated with a hapten, and an antibody binding to hapten reduces or inhibits the activity of the enzyme-hapten conjugate, the immunoassay is performed in accordance with conventional procedures. After a sufficient time, antienzyme is added which rapidly deactivates the enzyme, so that the signal remains constant for long periods of time.

Antienzyme termination in enzyme immunoassays

Background fluorescence which interferes with the measurement of an analyte in fluorescent immunoassays in serum samples is substantially diminished by treating the serum sample with a sufficient amount of a peroxidic compound, either organic or inorganic, for a time sufficient to reduce the background fluorescence contributed by serum components. The peroxidic compound is readily quenched, without adversely affecting the assay composition.

Reducing fluorescent background in fluorescent immunoassays

Methods and reagent combinations are provided for competitive protein binding assays for determining a member of an immunological pair (ligand and receptor) whereby an enzyme-ligand conjugate is employed in combination with an enzyme inhibitor, conveniently an antibody to said enzyme. When ligand is the analyte, receptor for ligand is also included in the assay medium, while supplemental amounts of receptor need not be added when receptor is the analyte. The assay is carried out in an aqueous buffered medium, normally at constant temperature, by combining in the assay medium the unknown sample suspected of containing the analyte, enzyme-bound-ligand, ligand receptor (antiligand), enzyme inhibitor (antienzyme), and enzyme substrates, and the enzymatic activity in the assay medium determined. By comparing the observed enzymatic activity with an unknown to the enzymatic activity observed in an assay medium with a known amount of analyte, the amount of analyte can be quantitatively determined. Kits are provided having matched amounts of enzyme-bound-ligand, antienzyme and, when appropriate, antiligand for use in the subject assay.

Antienzyme homogeneous competitive binding assay

Method and compositions are provided for determining the thyroxine binding capacity of serum, the value finding use in determinations of free thyroxine index. A competitive assay is performed where antibody for T-3 (anti-triiodothyronine) and serum thyroxine binding sites compete for T-3(triiodothyronine) in the assay medium: the T-3 is present as free T-3 added in a predetermined amount and T-3 conjugated to an enzyme. By combining the materials in a buffered aqueous medium with enzyme substrates, and determining the rate of reaction by the changing concentration of a light absorptive substance over a predetermined period of time, the thyroxine binding capacity of the serum can be determined.

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Mountain View, CA, United States of America

Robert A Yoshida