Vitamin B12 radioassay with oyster toadfish (Opsanus tau) serum as binder.
We describe a vitamin B12 radioassay in which oyster toadfish (Opsanus tau) serum is used as the binding protein. The serum is quite stable and has a high capacity and high binding affinity (K greater than 10(12) liter/mol) for vitamin B12. The binding is not significantly affected by temperature, the presence of denatured proteins, or the amount of vitamin B12 present. The radioassay is reproducible (CV 4.4%) within assay, 7.8% between assays) and sensitive (12 ng/liter). Assay accuracy is unaffected by the protein in serum or by reasonable variations in incubation temperature and time.
D000818:Animals; D002021:Buffers; D002352:Carrier Proteins / Q000097:blood; D003037:Cobalt Radioisotopes; D003486:Cyanides / Q000494:pharmacology; D005260:Female; D005399:Fishes / Q000097:blood*; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008722:Methods; D009994:Osmolar Concentration; D011485:Protein Binding / Q000187:drug effects; D012016:Reference Values; D013997:Time Factors; D014805:Vitamin B 12 / Q000097:blood*
D002021:Buffers; D002352:Carrier Proteins; D003037:Cobalt Radioisotopes; D003486:Cyanides; D014805:Vitamin B 12