title: Effects of instability of samples during liquid scintillation counting on the results of ligand-binding studies by equilibrium dialysis.
abstract: In binding studies using equilibrium dialysis, mixing of the aqueous samples with scintillation cocktails designed to accommodate aqueous samples produced grossly erroneous binding data. The amount of [1,5-14C]citrate apparently bound to rabbit muscle phosphofructokinase was a linear function of the citrate concentration, with no tendency to approach saturation, and highly variable. This problem was caused by very slow precipitation of citrate in the scintillation cocktail. Addition of a solubilizer stabilized the count rate during scintillation counting and resulted in acceptable binding curves.
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes; D002951:Citrates / Q000378:metabolism*; D019343:Citric Acid; D004355:Drug Stability; D007700:Kinetics; D008024:Ligands; D009132:Muscles / Q000201:enzymology; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D012588:Scintillation Counting / Q000379:methods
chemical_list: D002250:Carbon Radioisotopes; D002951:Citrates; D008024:Ligands; D019343:Citric Acid; D010732:Phosphofructokinase-1