DETERMINATION OF PROTEIN THIOL GROUPS BY ATOMIC ABSORPTION SPECTROMETRY

A method has been developed for the determination of thiol groups in proteins based upon the measurement by atomic absorption spectrometry of Hg bound to the protein-after reaction with HgCl2 or p-chloromercuribenzoate. The method is shown to be precise, accurate, and sensitive with a limit of detection of 0.1 μg Hg/ml. The increased sensitivity provided by the atomic absorption technique results in a 30-fold decrease in the amount of protein required for analysis by the usual spectrophotometric method. Analysis time is reduced significantly without loss of precision and accuracy by separation of excess unreacted reagent by gel filtration in place of dialysis. © 1969.