Biomaterial Database

Homogeneous enzyme immunoassay for triiodothyronine in serum. 2001

C D Karapitta, and T G Sotiroudis, and A Papadimitriou, and A Xenakis

Industrial Enzymology Unit, Institute of Biological Research & Biotechnology, The National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., 11635 Athens, Greece.

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. Conjugation caused inhibition of enzyme activity, and the enzyme conjugate was reactivated upon binding of anti-T3 antibody. Activation was blocked by the presence of non-antibody-bound T3; this was the basis for the development of the homogeneous enzyme immunoassay for T3 by determining GPb activity fluorometrically. RESULTS We used furosemide to block the interaction of T3 with serum proteins with T3-binding sites, avoiding any serum treatment step. T3 was measured in the range 0.3-8 microg/L. T3 values obtained by this assay correlated well with those obtained by a RIA (y = 0.97x - 0.07 microg/L; r = 0.96; n = 92). Within- and between-run imprecision (CV) was 5-9% for normal and high concentrations and 16-20% for low concentrations. CONCLUSIONS Chemical modification of GPb with a T3 derivative allows the development of a simple homogeneous enzyme immunoassay for T3 in unextracted serum.

UI	MeSH Term	Description	Entries
D007124	Immunoenzyme Techniques	Immunologic techniques based on the use of: (1) enzyme-antibody conjugates; (2) enzyme-antigen conjugates; (3) antienzyme antibody followed by its homologous enzyme; or (4) enzyme-antienzyme complexes. These are used histologically for visualizing or labeling tissue specimens.	Antibody Enzyme Technique, Unlabeled,Enzyme Immunoassay,Enzyme-Labeled Antibody Technique,Immunoassay, Enzyme,Immunoperoxidase Techniques,Peroxidase-Antiperoxidase Complex Technique,Peroxidase-Labeled Antibody Technique,Antibody Enzyme Technic, Unlabeled,Enzyme-Labeled Antibody Technic,Immunoenzyme Technics,Immunoperoxidase Technics,Peroxidase-Antiperoxidase Complex Technic,Peroxidase-Labeled Antibody Technic,Antibody Technic, Enzyme-Labeled,Antibody Technic, Peroxidase-Labeled,Antibody Technics, Enzyme-Labeled,Antibody Technics, Peroxidase-Labeled,Antibody Technique, Enzyme-Labeled,Antibody Technique, Peroxidase-Labeled,Antibody Techniques, Enzyme-Labeled,Antibody Techniques, Peroxidase-Labeled,Enzyme Immunoassays,Enzyme Labeled Antibody Technic,Enzyme Labeled Antibody Technique,Enzyme-Labeled Antibody Technics,Enzyme-Labeled Antibody Techniques,Immunoassays, Enzyme,Immunoenzyme Technic,Immunoenzyme Technique,Immunoperoxidase Technic,Immunoperoxidase Technique,Peroxidase Antiperoxidase Complex Technic,Peroxidase Antiperoxidase Complex Technique,Peroxidase Labeled Antibody Technic,Peroxidase Labeled Antibody Technique,Peroxidase-Antiperoxidase Complex Technics,Peroxidase-Antiperoxidase Complex Techniques,Peroxidase-Labeled Antibody Technics,Peroxidase-Labeled Antibody Techniques,Technic, Enzyme-Labeled Antibody,Technic, Immunoenzyme,Technic, Immunoperoxidase,Technic, Peroxidase-Antiperoxidase Complex,Technic, Peroxidase-Labeled Antibody,Technics, Enzyme-Labeled Antibody,Technics, Immunoenzyme,Technics, Immunoperoxidase,Technics, Peroxidase-Antiperoxidase Complex,Technics, Peroxidase-Labeled Antibody,Technique, Enzyme-Labeled Antibody,Technique, Immunoenzyme,Technique, Immunoperoxidase,Technique, Peroxidase-Antiperoxidase Complex,Technique, Peroxidase-Labeled Antibody,Techniques, Enzyme-Labeled Antibody,Techniques, Immunoenzyme,Techniques, Immunoperoxidase,Techniques, Peroxidase-Antiperoxidase Complex,Techniques, Peroxidase-Labeled Antibody
D007202	Indicators and Reagents	Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)	Indicator,Reagent,Reagents,Indicators,Reagents and Indicators
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D008297	Male		Males
D008301	Maleimides	Derivatives of maleimide (the structural formula H2C2(CO)2NH) containing a pyrroledione ring where the hydrogen atom of the NH group is replaced with aliphatic or aromatic groups.
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D011863	Radioimmunoassay	Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.	Radioimmunoassays
D001798	Blood Proteins	Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.	Blood Protein,Plasma Protein,Plasma Proteins,Serum Protein,Serum Proteins,Protein, Blood,Protein, Plasma,Protein, Serum,Proteins, Blood,Proteins, Plasma,Proteins, Serum
D005260	Female		Females