Biotin radioligand assay with an /sup 125/I-labeled biotin derivative, avidin, and avidin double-antibody reagents
We describe a new radioligand assay for determining biotin in biological fluids by using a mixture of N-(beta-(4-OH-3-125I-phenyl)ethyl)- and N-(beta-(4-OH-3,5-di-125I-phenyl)ethyl)biotinamides as radiotracer, avidin as a binding protein, and an avidin double-antibody as a separation reagent. The radiotracer is synthesized by coupling (at pH 8.5, 20-22 degrees C, 90 min) N-hydroxysuccinimidobiotin to radioiodinated tyramine. The assay curve is linear and the assay itself is sensitive (less than 10 ng/L), reproducible (intra- and interassay CVs 4.1% and 7.0%, respectively), and allows the simultaneous handling of more than 100 samples in less than 4 h. Serum samples from apparently normal subjects contained 100-840 ng of biotin per liter (mean 340 ng/L). Pregnant women had low concentrations of biotin (100-300 ng/L) in their serum. Patients undergoing chronic hemodialysis treatment showed high concentrations (0.5-3.0 micrograms/L), which may be ascribable to the inability of avidin, which was used as the assay binding protein, to distinguish biotin from biotinyl derivatives with an intact ureido ring.
- Research Organization:
- N.R.C. Demokritos, Athens, Greece
- OSTI ID:
- 5607769
- Journal Information:
- Clin. Chem. (Winston-Salem, N.C.); (United States), Vol. 33:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BIOTIN
RADIOASSAY
ANTIBODIES
IODINE 125
LIGANDS
PATIENTS
PREGNANCY
REAGENTS
AZOLES
BETA DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
IMIDAZOLES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
RADIOISOTOPES
VITAMIN B GROUP
VITAMINS
550201* - Biochemistry- Tracer Techniques